How To Test Ac Clutch Cycling Switch

Motors and relays are controlled by control panel knobs. 8L V6 1998 Ford Mustang stopped coming on when I turn on the "AC" switch. Honda Civic 1995 A/C won't work at hot !! control module and tested the AC switch around sunset. Getting hot here in FL. This pressure switch is electrically connected in series with the compressor. If you're here, chances are you've tried to recharge your AC system and found a compressor clutch not engaging issue. This product is made of high-quality materials to serve you for years to come. Some variants of the clutch cycling temperature switch comes with preset or adjustable settings for easy evaporator maintenance. Most imports utilize a high pressure switch to cycle the fan On smaller such vehicles a WOT Wide Open Throttle or low vacuum switch is employed ANd if you really want to get crazy Ford uses a Power Steering switch to save power and cut the compressor when theres a demand for power steering. The Chevy truck a/c system is a CCOT type system which stands for cycling clutch orifice tube. If there is voltage going to the clutch? a cycling switch may be bad, a fuse may be blown and the system may not have enough refrigerant pressure to trip the low pressure cutoff switch that cycles the compressor. This switch is made by GM to be an OEM stock fit in your C4 Corvette. Please note that this switch has a square connector, for 1998-1997 there is another switch that has a oval connector. They draw out all the freon using a machine with vacuum, after the freon is out the machine is still connected and the vacuum reading is monitored over a period of time to see if the vacuum holds. The center part (the clutch) should be engaged and should be spining along with the pulley. Inspect and test before replacing! AC Accumulator / Drier. connect the can, turn on the AC and wait a minute or so for the compressor to engage. Yes INSTALL a new A/C cycling switch. What year and model and engine? Is the compressor getting voltage?. just finally fixed a similar problem on my 2000 SE 3. not sure if the compressor can even be tested without a clutch so probably. The momentary push-button switch is a type of biased switch. If it is not coming on then check ac relay, cycling switch. Browse our selection and order online today. The clutch is pretty easy to test. Check the operation of the climate control and the A/C button. Note also that three of the switches would be cycled frequently during normal use: the ignition switch, the AC mode switch and the clutch pressure-cycling switch. So if I continue with the chart (as if the relay isn't cycling, I remove the relay, and jump two of the pins on the harness to see if the clutch engages, but it doesn't. When I got home I removed the 2-wire plug (on the AC), cleaned the connections and re-plugged the connector back on (actually unplugged and plugged a few times). 5 psi, disengaging the A/C clutch. Check the air conditioner fuse and replace as necessary. The air conditioning clutch relay transfers power, like a switch, from the interior A/C controls of an automobile to the A/C compressor, engaging the compressor clutch. You disconnect the wire connector at the compressor and put a lead to the battery to see if the clutch engages. To look at the condition of the compressor, you need an ac manifold gauge set so you can see the refrigerant levels in both sides of the ac system, and how well the compressor is working (if at all). Remember this low pressure switch is there for a reason. Stop by today. clutch relay. Four Seasons 35751 A/C Clutch Cycle Pressure Switch for Air Conditioning hl. I've determined that whatever provides the grounding path for the clutch relay does not do it. You now know what to do when AC compressor clutch is not engaging. the heater-A/C mode control switch; the low pressure cycling clutch switch; high pressure cut-off switch; compressor clutch relay; Powertrain Control Module (PCM). If you don't add more r-134 to the system and allow the AC compressor to cycle you will destroy the compressor. Also, ignoring a simple voltage check on the pressure switch can lead to repeated compressor clutch failure. There is no power to the A/C compressor clutch and it does not engage. Check the three wires again. For one test, I disconnected the clutch and replaced it with an unpowered test light -- this allowed me to check voltage drops with the a/c always on (pressure cycling switch would never open). Step 2 – Check for leaks. Don't have my multi-meter with me to check signal at compressor clutch connection. 5) OK, the Air Conditioning Compressor Clutch will not engage, so lets figure out why not. Dual-Pressure Switch. --Fuses OK-. Suspected Low R134, charged and still have the problem. They also changed the a/c relay as preventative. Do you have the draws ECM to AC clutch ralay, and instruction how to test it, Some thing is around ECM, AC realy, and AC clutdh switch. So far it working fine. ) Was thinking it could possibly be the switch in dash. When to replace your clutch plates: Warning signs By CarToq Editor - September 13, 2012 The clutch is one of the most important parts in a manual transmission car as it connects the engine with the gearbox, and is what provides motive force for the car. Understanding Defrost Cycle. Noticed my AC wasn't blowing cold (this was the first time I had it on this season), so I pulled over and saw that the clutch is not engaging. Next check clutch itself. This will help you keep the threading intact on the unit, as well as make sure that you do not drop any debris into the accumulator. When the pressure returns to normal, the cycling switch will close. Signs that your A/C clutch cycling switch may be failing include a lack or total loss of cooling in your A/C system. I did touch on the operation and the basic principles behind how the converter clutch works on my page about the transmission valve body if you want more information. Just trouble shooting to see what is wrong before paying for work. Junior Member. ECM judges whether compressor can be turned ON, based on each sensor status (refrigerant pressure sensor signal, throttle angle, etc. Search With Vehicle An air conditioner clutch cycling switch measures pressure to detect the flow of refrigerant in your system by sitting in the low pressure side of your A/C. If you experience any problems with the site, please contact Pete Hoffman immediately so corrections can be made. This is controlled by the low-pressure switch, which is installed on the accumulator. 2 - IF the hi/lo pressure switch only effects the control signal (coil side) of the compressor relay and is NOT in series with the clutch itself then my contact shorting test above proved that the compressor clutch is wide-open and thus bad. The cycling switch cycles the compressor on and off on the low side of the system. My AC has gone out. Some Hondas have something like the A/C clutch cycling switch, but it is located with the evaporator coil (under the dash). When it comes to your Ford Expedition, you want parts and products from only trusted brands. it's job is to prevent freezing up the evap if the low side drops to low. Do NOT jump the low pressure switch to operate the compressor non-stop so you can add refrigerant. This switch is on the accumulator and cycles the compressor clutch. 1992 Chevy 4x4 1500 5. So, we'll begin by discussing automotive air conditioning theory of operation. So I go looking for the AC compressor clutch cycle switch so I can short the wires to keep the compressor engaged. Which wires do you jump around to get current to the clutch so I can add enough freon to get the low pressure switch to allow current to the clutch?. Buy ACDelco 15-5715 GM Original Equipment Air Conditioning Clutch Cycling Switch: Clutches - Amazon. Next step is this: "Check voltage at pin 'A' of compressor clutch". A/C-heater system is a blend-air system. The HVAC control head determines a low charge by monitoring the circuit from the pressure cycling switch. So 35 PSI R134a is 40 degrees - the range the switch should kick off the compressor. Buy ACDelco 15-5715 GM Original Equipment Air Conditioning Clutch Cycling Switch: Clutches - Amazon. Upload your own picture of the Mustang Air Conditioner (A/C) Clutch Cycling Switch R-12 (82-93) Please make sure to hold your device horizontally (like a camera) rather than vertical (like a phone). There is no power to the A/C compressor clutch and it does not engage. problem could be in the eatc module that send power to purple wire that feeds the ac pressure cutoff switch and ac clutch cycling pressure switch then feeds the ac compressor clutch solenoid. Free shipping. The link below will lead to a PDF with some technical info in it that will help troubleshooting. Inspect the motor coupler. If you jump the low pressure switch with the engine running, do it only for a few seconds. Cycle through low, medium and high settings. When it comes to your Hummer H2, you want parts and products from only trusted brands. Noticed my AC wasn't blowing cold (this was the first time I had it on this season), so I pulled over and saw that the clutch is not engaging. ) Potential Causes: A/C Compressor, A/C Pressure Sensor F129, A/C Switch, Ambient Temperature Switch F38, Battery Auxiliary Fuse Box, Fan Control Module J293 (and Wiring), Fuse or Lost Throttle Basic Settings. If A/C system passes the Field Test, no further service is necessary. In this tech article VETTE provides an air conditioning troubleshooting guide to show you how to diagnose and repair common Corvette A/C problems - Vette Magazine the low-pressure switch will. Technician A says this is a normal condition. Next suspect, Pressure cycling switch, O'reillys computer doesn't show the car to have one. com ® permission to use it in future advertisements and promotions. Although most cars can blow air at temperatures as low as 60 degrees, the temperatures inside the evaporator core can get cold enough to completely freeze the entire core. Step 6: Install New Cycling Switch. If you have a situation where your car's air conditioner compressor clutch doesn't engage, try the troubleshooting techniques described here. I don't know if the clutch is spinning, can't really see it. The manual shows #5, #22 or #24 and #105 as fuses for the system. The switch is a Normally Open (NO) and closes on Pressure Rise above the Setpoint, enabling the Clutch if the other conditions are met. Global Parts Distributors, L. 3 things to check. Tech B says there can be an air flow obstruction at the condenser. 5 air conditioner check. Seeing as how it's reading MUCH higher than that, I don't think the compressor is engaging. not sure if the compressor can even be tested without a clutch so probably. This will bypass the low pressure sensor and allow the AC clutch to engage and begin to cycle again. Another thing the clutch puller / installer #78-3213 works really good. A full cycle of AC uses the entire wave of the south and north magnets. (GPD) has been a known supplier of AC parts in the automotive market for many years. With the sytem on, set at max cool, take the connecor off the pressure switch and one terminal of the wire should have battery volts. It sounds like it may have a faulty clutch cycling pressure switch that's screwed into or near the accumalator/dryer. My AC would randomly start and stop intermittently, so I ensured that the system was charged and once I was assured that it was full I checked this switch and it was the culprit. It looks like it's running when I peek down into the bay. This will help you keep the threading intact on the unit, as well as make sure that you do not drop any debris into the accumulator. Can You Guys Help w/my Silverado AC Clutch/Compressor? Discussion in ' Troubleshooting & Diagnosis ' started by gordonquixote , Jul 16, 2011. Pressure Temperature Table. You pop the hood and the the Air Conditioning Compressor Clutch will not engage, so lets figure out why not. If you turn on the air conditioning and stand in front of the car and listen to the engine you will hear the AC compressor clicking every few seconds as it engages and disengages. my ac system blows hot air so i thought the pressure was low, and got a can of r-134a and added it. Air Conditioning Clutch Cycling Switch Stay with the parts brand your vehicle came with and get the GM quality you know and trust with ACDelco GM Original Equipment Air Conditioning Parts. If you are seeking top-quality and affordable air conditioning parts for your vehicle, then UAC products offered at CARiD are what the doctor ordered. These Blower Control Switch ensure dimensional stability and function with extended durability. Universal Components 12inch Black Doorguard Exterior Styling Universal Black Door guardSnap on protectorSimple and easy to fitFits on most car doorsSize: 12 Inch. ) Was thinking it could possibly be the switch in dash. just the AC clutch. Check ac clutch fuse then check for voltage at the connector to the clutch. Low AC pressure will prevent the relay from sending power to the AC compressor clutch. The clutch cycling switch cycles the compressor according to the pressure in the accumulator. On some models, a light will illuminate on the A/C push button when switch is activated. I know its probably the compressor but the only thing I'm not able to check is the A/C Clutch Diode. Check the blower fan. With the ignition key on, unplug the low pressure switch (clutch cycling switch) and place a jumper wire across the connector. I then jumped the AC relay to and noticed the clutch would cycle erratically despite being commanded on. Car AC Clutch Wont Engage When the car AC clutch won't engage you turn on the air conditioning and patiently wait for cool air that never comes. Well, I listened at the relay while my wife turned cycled the AC on and off but I don't hear any click. It goes on when the AC clutch engages. From the fuse, that circuit goes to the A/C selector switch, then to the cycling switch, then to the high-pressure cut-out switch, then to both the PCM and the A/C relay in the CCRM. Four Seasons 35751 A/C Clutch Cycle Pressure Switch for Air Conditioning hl. 5) OK, the Air Conditioning Compressor Clutch will not engage, so lets figure out why not. I believe blk/yel is low side pressure and dk grn/org is high side cut off. Check the relays. Next suspect, Pressure cycling switch, O'reillys computer doesn't show the car to have one. Technician B says the air conditioning system is overcharged. Does the clutch engage when you jump the relay terminals? If not, check for 12V+ power at the relay itself. Step 2 – Check for leaks. NOTE:- The dye check will. 5 psi, disengaging the A/C clutch. Find Ac Compressor Bearings in stock and ready for shipping here! Parts Supply Online Shop. this is a signal that goes from the hvac control module to the switch then to the PCM input. 12V wire is the hole one of the pins on the switch plugs into. Test the centrifugal switch. Does Compressor Run The compressor should run. I can manually fire the relay plug and the clutch turns on. compressor clutch still didn't engage. I know that the Evap. Next, I popped the clutch single wire terminal. You can next try jumping the pressure switch(es) to see if you can get the compressor to operate. I've determined that whatever provides the grounding path for the clutch relay does not do it. Buy online, pick up in-store in 30 minutes. Check belt tension. Note also that three of the switches would be cycled frequently during normal use: the ignition switch, the AC mode switch and the clutch pressure-cycling switch. Introduction: This bulletin announces the availability of a new Air Conditioning compressor / clutch assembly to address customer concerns of the system not operating. Accumulators are on the low side of the system between the evaporator and the compressor. The AC cycling switch de-energizes the clutch and stops the compressor if the pressure gets below a certain level. During winter months many heat pumps will need to go through a “defrost” cycle during operation. Inspect the motor coupler. The thermistor should be suspected if you have excessive cycling, but normal pressures as did the OP. If the pressure is rising the switch will close at 31. Just trouble shooting to see what is wrong before paying for work. If it isn't, you need to find out why not. I checked fuses and such and everything looks okay to the compressor and clutch. They did a pressure test as well to make sure no leaks. Orifice tubes can become clogged and severely hamper A/C performance. It could still have either a cooling system issue or electrical issue with in the AC, climate controls, or mechanical issue with the Ac such as the Expansion valve. Turning off the AC and then back on has resolved the problem in both cases. If you have power at the clutch connector and a good ground, then you you may have an open coil (should be around 3-5 ohms) or the aforementioned excessive clutch gap. Check out free battery charging and engine diagnostic testing while you are in store. The best part is, our Ford Expedition A/C Clutch Cycle Switch products start from as little as $11. High pressure and low pressure cycle switch. This is a good thing. If nothing is coming through your air conditioning vents, the blower motor has a malfunction and needs to be replaced. The purple 5. The momentary push-button switch is a type of biased switch. Check clutch electrical circuit for proper voltage per OEM specifications. Refill it until the pressure is about the same as the air temperature. The first test should be to check the pressure in the system. Although full current was never approached (the light draws only about 300 ma), I did find bad connections. It is engaged and disengaged as needed by an electro magnetic clutch. UAC's line of electrical components includes the Switches and Relays that are necessary for the proper function of an A/C System. With the low pressure switch cycling switch jumpered, engine off, ignition in RUN, mode switch to one of the A/C settings, you should have battery power at one of the clutch connector pins assuming it was present at the cycling switch. Stop by today. 6 PSI and the pressure of R-134a is 22. Orifice tubes can become clogged and severely hamper A/C performance. --Fuses OK-. A/C-HEATER SYSTEM 1995 Chevrolet Tahoe 1995 AIR CONDITIONING & HEAT General Motors Corp. 8 IN, Package Length--1. You pop the hood and the the Air Conditioning Compressor Clutch will not engage, so lets figure out why not. Check ac clutch fuse then check for voltage at the connector to the clutch. use volt meter and check for voltage at both switches. You disconnect the wire connector at the compressor and put a lead to the battery to see if the clutch engages. Also check the compressor mountings for tightness. If the fan moves half an inch or more, something's wrong inside the clutch. Then, check the wiring harness sections in between these parts for breakage or worn insulation. If so, try the troubleshooting techniques described here. With fans working as you describe, this is Hondas' order for troubleshooting. TEST the system for normal operation. The switch I'm wondering about is the one to the right of the intake, left of the red cap on the AC system. dk grn/org pulls power from the clutch cyling switch -> hvac unit/ac on switch -> fuse 26. When I got home I removed the 2-wire plug (on the AC), cleaned the connections and re-plugged the connector back on (actually unplugged and plugged a few times). its easy enough to test by jumping the two pins on the male connector and seein. The AC will turn on if I jump 12V to the blue/yellow wire in the pressure switch near the radiator. It could still have either a cooling system issue or electrical issue with in the AC, climate controls, or mechanical issue with the Ac such as the Expansion valve. Inspect the motor coupler. ) Was thinking it could possibly be the switch in dash. To run the self-diagnostic function, do the following: 1. Random Jumping devices can cause lots more DAMAGE than you will want to pay for someone to repair. The HVAC control head determines a low charge by monitoring the circuit from the pressure cycling switch. APAds prolongs the life of your air conditioning system components and reduces A/C maintenance costs. The clutch is always disengaged and the compressor pulley rotates freely untill you switch on the AC. my ac system blows hot air so i thought the pressure was low, and got a can of r-134a and added it. ) Potential Causes: A/C Compressor, A/C Pressure Sensor F129, A/C Switch, Ambient Temperature Switch F38, Battery Auxiliary Fuse Box, Fan Control Module J293 (and Wiring), Fuse or Lost Throttle Basic Settings. You can also use a jumper wire to jump the two terminals that pass electrical current onto the air conditioning compressor. One of the most common problems is a low refrigerant charge, the low pressure switch prevents the AC clutch from engaging when the system is low on refrigerant. The cycling switch's cut-on and cut-off pressures are readily available in manuals; therefore, its operation can be monitored by the manifold gauge set and you can tell whether its working properly or not. Resistance should be 58 ohms to 78 ohms both ways. Figure out what's wrong with your car's A/C and fix the problem yourself, all for less than the diagnosis alone would cost at most auto repair shops. TEST the system for normal operation. A full cooling cycle occurs from the time that the unit kicks on to the time that the temperature you set at the thermostat is reached and the unit kicks back off again. This is a MOPAR replacement AC Low Pressure Switch for the above listed Jeep applications. Honda Civic 1995 A/C won't work at hot !! control module and tested the AC switch around sunset. Does the clutch engage when you jump the relay terminals? If not, check for 12V+ power at the relay itself. Which wires do you jump around to get current to the clutch so I can add enough freon to get the low pressure switch to allow current to the clutch?. I did that to mine while I was replacing all the o-rings in the system. The switch on the accumulator is to keep the evaporator from freezing up by cycling the compressor clutch. The clutch is always disengaged and the compressor pulley rotates freely untill you switch on the AC. Hopefully it’s just a bad coil though. Learn More. On the clutch cycling switch right rear of engine bay (2 pin) check the red/yel for power. I found out how to test the A/C Clutch Cycling Pressure Switch , long story short its not working. Is possible that a bad Diode could stop the A/C from working? And is there a way to test it? 2002 Venture 104,000km No way. The AC clutch is the same basic design as an electric PTO clutch. The clutch cycling switch cycles the compressor according to the pressure in the accumulator. If the clutch does not engage, use a voltmeter to check for 12 to 14 volts at the pressure switch. Repair as necessary. Resistance should be 58 ohms to 78 ohms both ways. Test the water level switch. It could still have either a cooling system issue or electrical issue with in the AC, climate controls, or mechanical issue with the Ac such as the Expansion valve. Air conditioner cycle switches can also fail. The switch has a square connector. If I bypass the switch nothing happens at all though. If you are troubleshooting your system, you may also want to test the pressure switch itself. Please note that this switch has a square connector, for 1998-1997 there is another switch that has a oval connector. 5 seconds, ten times in a row, the control head assumes a low charge and disables the compressor until reset. It will still cycle when the switch is in Defrost or AC. Please help!. the AC has already had a r134 adapter attached to it, vacuumed the system out, put in enough 134 till the compressor I believe was supposed to kick in and take the rest of the can. on the 4 pin dual pressure switch check for ground on blk/yel and power and dk grn/org. Check the black wire for ground. This is because the pressure temperature relationship of R-12 and R-134a is different. The clutch may be bad. One of the things missing in the Pantera air conditioning system is a high/low pressure switch. You can adjust it one turn counter clockwise (that should do it) until it cycles the compressor at about 21psi. During winter months many heat pumps will need to go through a “defrost” cycle during operation. By using a diode, you take and block the positive side of the AC and only use the DC or negative side to charge a battery (see Figure 2). The fan clutch is just what the name says, it is a mechanism that will clutch the fan on and off depending on the need for more or less cooling air to flow thru the radiator. I took a check and the freon was fine. Jumping the pressure cycling switch is common practice on domestic CCOT systems, but the Civic is temperature cycled and fully controlled by the ECM. Place an ohm meter probe on each pressure switch terminal and verify the switch has continuity. This will usually happen when a condenser fan fails. I've encountered the same problem (flashing AC indicator on climate screen) a couple times. You have to add freon till theres enough to start the system. TEST the system for normal operation. when i jump the terminals on the relay it comes on and cools like a champ. not cycle then you will need to check the. In the process, you learn that the ac relay is integrated component of the fuse box and not replaceable. In ambient temperatures below 30° F, the A/C cycling switch will not allow compressor operation because of low system pressures. Remove the component from the socket and test for a power signal and a good ground at the proper terminals. my ac system blows hot air so i thought the pressure was low, and got a can of r-134a and added it. If the clutch does not engage, use a voltmeter to check for 12 to 14 volts at the pressure switch. Find many great new & used options and get the best deals for A/C AC Clutch Cycle Switch-Clutch Cycling Switch UAC SW 10082C at the best online prices at eBay! Free shipping for many products!. Biggest selection of ac compressor bearings and many comparable listings. Check resistance both ways. Tech A says the high pressure cut out switch could be defective. it will cycle on and off very quickly at the start as the pressure drops, then builds. 2)ECT sensor 169-194F, TP sensor about. If low on refrigerant the cycling clutch switch will be open at the H / expansion valve at the firewall. By continuing to use this site you consent to the use of cookies on your device as described in our cookie policy unless you have disabled them. and pressures are related) if pressures indicated are good, there could be a number of problems. The switch has a square connector. If unsure, check with the manufacturer's manual for specifications and special procedures for performing the A/C clutch coil test. You can do it the way mentioned above, or you can test it another way. Both times were at initial startup in the morning. Getting hot here in FL. just the AC clutch. The cycling switch screws to the top of the accumulator / drier. check for a short or open in red yellow wires at the ac pressure cutoff switch. At some conditions, GM Low Pressure Switch Cycling is expected. A cycling clutch switch is used to engage and disengage the compressor clutch according to the system’s low side pressure. An AC clutch cycling switch is used to determine low side A/C pressure (which is directly proportional to temperature). occasionally this is enough to make the high pressure transducer see correct pressures and start to. Goes off when the clutch disengages. It does this to prevent your evaporator from icing or freezing as it operates. Many technicians are aware that the pressure-cycling switch opens every time. The accumulator is usually found at the back of the engine compartment, mounted to the firewall. The AC clutch is the same basic design as an electric PTO clutch. Typically clutch cycling for temperature control is used in conjunction with a fixed orifice tube instead of an expansion valve. Next moved on to the pressure and cycling switches (located on accumulator and compressor discharge tube) Again, they tested good, but I had spares, so replaced them anyway. If the clutch does not engage, use a voltmeter to check for 12 to 14 volts at the pressure switch. Also yesterday I found both the brown wires that go to the ac thermostat had melted together and shorted out. If the vacuum reading holds you dont have a leak in the system, then the system is recharged to spec. A/C Clutch Cycle Switch (SW9701C) by UAC®. The cycling switch cycles the compressor on and off on the low side of the system. If it is not coming on then check ac relay, cycling switch. I changed the selector switch on the dash to all positions one at a time and observed the AC compressor. I believe the fuse is a 40Amp located under one of the the relay panels under the dash. The FOUR SEASONS Ac Clutch Cycle Switch contains no remanufactured components, and is designed to operate in either city or highway driving. It will still cycle when the switch is in Defrost or AC. jumped pressure switches with no change. This clutch engages whenever the dash air controls are set to activate the air conditioning, however various safety switches will switch off power to the clutch if the pressure is too high or too low or the evaporator is to the point of freezing up. The AC will turn on if I jump 12V to the blue/yellow wire in the pressure switch near the radiator. 2)ECT sensor 169-194F, TP sensor about. In cycling clutch systems with a fixed orifice tube, a low-pressure or cycling clutch switch is placed in series with the compressor clutch circuit so it can turn the clutch on or off. If the switch had contimuity static, and the clutch does not engage, then test the coil in the clutch for continuity. Hydraulic Valve Check 3/8" system Single Oil engine NPT way pressure high Pump Pump way high pressure Hydraulic Oil engine Single Valve NPT 3/8" Check system YS F-91 AC Super Charged w/ Pressurized Fuel System 4 cycle nitro engine new YS F-91 AC: $152. Buy online, pick up in-store in 30 minutes. Your car's air compressor pressure switch, is responsible for giving and cutting off power to the air compressor of the air conditioning system. This will bypass the low pressure sensor and allow the AC clutch to engage and begin to cycle again. You can also use a jumper wire to jump the two terminals that pass electrical current onto the air conditioning compressor. With the ignition key on, unplug the low pressure switch (clutch cycling switch) and place a jumper wire across the connector. There are two basic types of automotive air conditioning systems. Disconnect the connector and while being careful, short the two wires together while the truck is cranked and see if the clutch clicks and the compressor spins. Clothes are too wet after spin cycle. Before performing symptom troubleshooting, check for powertrain DTCs. That fuse doesn't feed the A/C clutch directly, so overdrawing current from a bad A/C compressor or clutch won't cause it to blow. With the AC compressor running it should read ~40psi. This could be a Freon problem, a restriction in the system problem, compressor or compressor clutch problem or an electrical or control problem. But that tells me if the system is mechanically okay and performing properly. For information on the specific function of the A/C cycling switch, refer to the Workshop Manual Section 412-00 Climate Control System. Yes INSTALL a new A/C cycling switch. Have checked at fuse panel, good there, not getting any voltage at any points in engine compartment, (pressure switch, clutch, etc. So I am guessing the clutch cycling switch. Function of the ac compressor Cut-off switch in a vehicle. Check blower switch for voltage at each position. I know its probably the compressor but the only thing I'm not able to check is the A/C Clutch Diode. Take caution when doing this as you can cause damage if you are not familiar with how your AC electrical system works. If low on refrigerant the cycling clutch switch will be open at the H / expansion valve at the firewall. System pressure testing and diagnosis System temperature checks A simple but effective initial test is to check the temperature of the refrigerant system components and lines by touching them while the system is operating. 5 psi, disengaging the A/C clutch. In this tech article VETTE provides an air conditioning troubleshooting guide to show you how to diagnose and repair common Corvette A/C problems - Vette Magazine Clutch-cycling switches. Inspect the pulley. A replacement clutch, coil, and pulley (always replace them together) fixed the problem. In isolated situations where the AC compressor clutch relay has a unique part number we test it the old-fashioned way.