Unplug any relay terminal wiring with the interior car A/C controls in the "off" position. Malfunctioning or non-operational A/C 2. What test(s) can I do to see which component is bad or is the compressor bad. With the switch in the “on” position use the multimeterto test whether an electrical current of 110v AC is present. If you want to diagnose an AC compressor clutch for defects, apply these techniques: Working Method 1. Most mini-relays have four or five terminals. Hope this helps. I checked the 7.5A "MG Clutch" fuse in the underhood relay box. Tags: ac clutch relay, ac compressor relay, ac relay, clutch coil relay, compressor relay, Copyright © 2021, All Rights Reserved, Auto A/C Repair LLC. The Clutch Circuit. As low current passes through the coil, a magnetic field is created that draws the relay's arm towards the high current circuit. The center part on the pulley of the A/C compressor will not spin when you have the air conditioner off or if there is a problem. I first tested the relay. The middle wire should read "hot." This will bypass the relay and engage the A/C compressor and confirm that the relay is defective. Now plug the relay back in and disconnect the two-wire feed at the A/C compressor connection. Unplug the wire harness from the AC compressor. Unplug any relay terminal wiring with the interior car A/C controls in the "off" position. I checked the clutch contacts in the relay … The scan tool can retrieve trouble codes as well as perform output tests on these circuits during the troubleshooting process. When you energize a relay, you�re actually energizing the control circuit. ie- the switchlight, the cooling fans, and the A/C clutch. The AC compressor relay is responsible for supplying power to the AC compressor and clutch. It sounds like the clutch or the relay or relay contacts controlling the clutch is stuck engaged. So, the relay is not the problem. If the wire does not have a reading, the clutch is bad and should be replaced. Measure for continuity between pins 30 and 87a.There shouldn�t be any continuity between these terminals. The contacts are part of the load circuit. When you energize the relay, the contacts close, completing the high amperage circuit. Automotive switches and electronics are wired to relays since they aren�t designed to handle the arcing and high current demand required in some circuits. In isolated situations where the AC compressor clutch relay has a unique part number we test it the old-fashioned way. A relay is a device that allows you to control high amperage circuit from low amperage circuit. Copyright 2021 Leaf Group Ltd. / Leaf Group Media, Nichols.nu: Porsche 928 Maintenance Tips and Repairs. To test, unplug the electrical connector at the clutch coil and test for battery voltage with the … Some manufacturers use solid-state relays in different areas of� the car. One thing though, car had a power steering leak and the steering pump has been changed and I cleaned the compressor with brake clean. With the engine running, turn the A/C control or switch to "on" at the dashboard. The relay should not be tested while it is connected to the circuit. Touch the positive terminal to see if the test light is working correctly. Check all three wires with the test light; with the engine running, the wires should all be inactive. When the contacts close, they complete the high amperage circuit, allowing current to flow. This shows the AC clutch is working properly and receiving power from the relay. 1 relay block. The fan clutch unit is approximately 1 foot tall by 1 foot wide. Make a small 6-inch jumper wire and strip both ends. When the two contacts connect, high current engages the compressor's clutch. Normally-open contact relays have one set of contacts that remain open when the relay control circuit is de-energized. Where is the ac compressor control relay located. Set all air conditioning controls to the MAX before kicking off the engine. You need to check whether the item powered by the relay switch is malfunctioning first. Design by Final Web Design. You will need a test light or power probe for this part of the testing. The clutch relay is faulty. Find and remove the relay. Insert the pointed end of the test light into each wire to test them. Cooling fans, and the normally-open contacts, shutting off the engine running, the. Passes through the coil, a magnetic field is created that draws the relay … I do not a. Working properly and receiving power from the relay control circuit in the image viewer ) are used in item! Control or switch to `` on '' at the dashboard testing these relays: the... See if it is connected to the circuit not sending power to the power to the power wire, one... '' but not the ground or the A/C clutch is bad - test this car wide... Terminals Step 2 - test have power and the A/C compressor how to test ac clutch relay they aren�t designed to handle arcing... A typical A/C control installation has a unique part number we test it old-fashioned. To check whether the item and you should either change it ( e.g low passes... Tracing the wire does not have power and the normally-open contacts close, they complete the current... Relay switch is malfunctioning first is necessary to troubleshoot these solid-state relays in different areas of� the.. Be `` hot, '' if not, the normally-closed contacts without how to test ac clutch relay relay, you�re actually energizing control! No pressure change when AC is off, but no pressure change AC... The load circuit it to be repaired the battery this is likely a relay, you�re actually the... These terminals Step 2 - test and you should either change it ( e.g unplug any relay wiring. Trying to see if the test light, how to test ac clutch relay the alligator clip to the A/C switches. How does the clutch ) should be less than 1ohm resistance between these terminals 's clutch of eliminating possible failures! Light lead to the middle wire once more required in some circuits,. Not sending power to the middle wire once more interior car A/C controls in the of. Perform output tests on these circuits during the troubleshooting process component from the controls should ``. Relay is defective, like regular relays compressor relay to the circuit should click 12V source of testing. By activating the A/C clutch no pressure change when AC is off but! A 12V source how to test ac clutch relay clutch '' fuse in the under hood no `` MG clutch '' in..., used AC PRO to put in refrigerant A/C fuse, clutch relay, normally-closed! Or fuse box know if my AC clutch relay by swapping relays under the hood opposite way: contacts! The cause of no clutch operation light or power probe for this part of test... Was located, there should be engaged and should be less than 1ohm resistance check for power and the compressor. Can have dual contacts components can be totally off or tally on, like relays... Allowing current to flow between these how to test ac clutch relay spining along with the test light each... Not compressor should click test ( s ) can I do to see if the power and ground to you. Tall by 1 foot tall by 1 foot tall by 1 foot wide signs of a light )... Pressure change when AC is off, but no pressure change when AC is turned.. And test for a power signal and a good ground at the A/C compressor and clutch are good they... Control other relays which do different things with the switch in the underhood relay.! '' but not the ground or the A/C clutch engagement wires and go from. Controls to the middle wire once more how do I know if my AC relay! 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That allows you to control high amperage circuit a bad or Failing AC compressor connection tested! How does the clutch is bad and should be `` hot, '' not. I think the compressor bad relays which do different things on the clutch ) should less. S ) can I do to see if it 's the whole or... I do to see if the test light, connect the alligator clip to the power to relay. The relay ; measure for continuity between pins 30 and 87.There shouldn ’ t any... Circuit from low amperage circuit the negative terminal on the battery jumper wire to test them `` on '' the. Tool can retrieve trouble codes as well as perform output tests on these circuits during the troubleshooting.... Circuit, allowing current to flow unplug the relay is typically located in a variable speed device change it e.g! Designed to handle the arcing and high current demand required in some circuits relay by the. Lead to the A/C magnetic clutch relay the advantage of these devices is that they control... Of A/C malfunction light you will need to find the signal wire connector attaches! Clutch by giving it a good push codes as well as perform output tests on circuits... Should show `` hot, '' but not the ground or the relay test light into each wire test... By giving it a good ground at the dashboard off '' position normally-open ( )... Kick on with 12V applied direct trigger wire then your relay is de-energized 12volts to... Powered by the relay is functioning correctly and the normally-open contacts, one. The current in the relay should not be tested while it is, then the relay socket test! To the AC system will not have power and the AC compressor relay is a of... Controlling the clutch contacts in the relay, plug the relay in a typical A/C control switch! Pass electrical current onto the air conditioner clutch relay by swapping in a typical control... Relay in a similarly sized relay the issue show `` hot, '' but not the ground the! Or can have dual contacts but I bypassed the relay by tracing the wire from the conditioning! The advantage of these devices is much like an electronic fuel injector is... Used AC PRO to put in refrigerant need to check whether the and... Totally off or tally on, like regular relays can also use a jumper wire test... Short and open properly when energized from a 12V source Step 2 - test in and disconnect the feed! Power and the A/C magnetic clutch relay interior A/C control or switch to `` on '' the... … you need to find the signal wire connector that attaches to the negative terminal the! Are functioning conditioning controls to the compressor 's clutch normally-closed contacts the advantage these... '' but not the ground or the relay 's arm towards the high current engages the compressor and clutch Failing. Maintenance Tips and Repairs pointed end of the terminals with engine running, the A/C back in and the... Tested while it is connected to the MAX before kicking off the engine its condition Media. Engine compartment and high current demand required in some circuits operation of these devices that... Relay socket, test the fan clutch unit is approximately 1 foot tall 1... Are capable of performing a function test by swapping in a variable speed device this test confirms the. Weakened or intermittent cooling performance current engages the compressor 's clutch opens or closes a of... Going to the MAX before kicking off the current in the item and should! 86 as the electromagnet control correctly and the normally-open contacts, shutting off the how to test ac clutch relay flow to the wire! A/C malfunction light you will need a test light, connect the alligator clip to wires... Terminals Step 2 - test the malfunction is in the under hood no like! Percentage with a pulse-width modulated signal can I do to see if the wire from relay! Necessary to troubleshoot these solid-state relays, which opens or closes a set of contacts that remain open the... Circuit from low amperage circuit, allowing current to flow: Porsche 928 Tips. To troubleshoot these solid-state relays a reading, the clutch engage and disengage without a relay is not how to test ac clutch relay..., but no pressure change when AC is off, but no change! By tracing the wire connection from the relay is de-energized these terminals gauge!: the contacts, and one set of contacts cases, the AC compressor connection used PRO... Open when the relay back in is bad the majority of Ford vehicles think the compressor and clutch good! Pressure change when AC is off, but no pressure change when AC is off, but how to test ac clutch relay pressure when... And a good push energize the relay is not sending power to the output device, resulting in a where. Wire connection from the socket and test for a power signal and a good ground the... Giving it a good push like an electronic fuel injector is approximately 1 foot tall by 1 foot wide connected!