|
AC Compressor Clutch Won't Engage
Hi folks, I could use some help. No AC in my 2008 Fit Sport after turning on the first time since probably October 2018. Tried a cheap Walmart $20 recharge kit hoping the pressure reading would guide me. Put my AC on max and popped the hood. Pressure was high. A guy at Auto Zone said that didn't surprise him since the clutch wasn't engaging. He told me I wouldn't recharge the system or get an accurate reading until that was engaged. He said I could bypass the pressure switch by running direct to 12v. I swapped AC fan and AC compressor relays to rule out relay failure and even went so far as to jump the relay with a paper clip but no luck. I know I was jumping correctly because I could get the fan spinning but couldn't get the clutch to engage. Wires off compressor seem to be looking good. Any ideas? |
Start with the fuse #10 (7.5A) in under dash fuse box
If bad try different a/c switch If good, probe a/c clutch connector [single wire] with test light (easier said than done) the light should come on with engine running and a/c switch on and fan on 2 speed If light is on inspect the clutch coil (will need to remove wheel, under cover , etc. PS I bet the topic starter will never follow up:) |
No luck
Ok I inspected the fuse. It looked fine so I moved on. I unclipped the wiring coming directly off the clutch and compressor. Three positive/red lines feed into the connector. I hooked up the ground on the clutch to ground battery and positive on the battery to each of the three options on the clip connector one by one since it was hard to tell which positive line went to the clutch. Nothing. From what I understand I would hear a click when the magnet engages. Also just so it's out there I did use a multimeter to test the end of the jumper lines I rigged up and was getting the correct voltage. I know I properly tested this. So....I jacked up the front right end and took off the wheel. AC clutch spins but seems rough. What am I looking for to tell if the clutch is bad? I'm about at the point where I don't want to do much more on my own. Pulling the entire unit out of a fit isn't exactly the easiest and I'm light on tools and workspace. |
Let's do this
plug connector back remove the ground wire from compressor (yellow arrow) https://cimg8.ibsrv.net/gimg/www.fit...04ab3c265f.jpg attach one end of 3 feet wire wire to this ring connector attach other end of this wire to the positive probe of voltmeter or test light (preferred) connect negative lead to the good ground route this 3 feet wire away from the belt and fans start the engine and turn a/c on the light should be on (not very bright) if clutch circuit is not interrupted (voltmeter will indicate 12 volts in this case) |
Start engine. Turn on AC. I know you say the compressor does not turn on (clutch does not engage) but do the radiator fans turn on? (important clue)
If fans do run and you already checked the relay, look for a problem with the compressor clutch---field coil open circuit? Gap between clutch plate and pulley is too large? (ideal is about 0.5 millimeter gap) Three positive/red lines feed into the connector. I hooked up the ground on the clutch to ground battery and positive on the battery to each of the three options on the clip connector one by one since it was hard to tell which positive line went to the clutch. Nothing. |
Thanks for the help folks. Turned out there's no avoiding a new compressor and while I'm at it a new condenser (looks like Swiss cheese). Making sure it wasn't a more simple issue was important to me and I appreciate all your help in self diagnosing the situation. Very cool forum/site.
|
Originally Posted by ezone
(Post 1423586)
Start engine. Turn on AC. I know you say the compressor does not turn on (clutch does not engage) but do the radiator fans turn on? (important clue)
If fans do run and you already checked the relay, look for a problem with the compressor clutch---field coil open circuit? Gap between clutch plate and pulley is too large? (ideal is about 0.5 millimeter gap) Center wire is for the clutch field coil. The two outer wires are for the thermal protector--- which must have continuity, and the system cannot operate if you have the compressors 3 wire connector unplugged (fans will not even turn on when ou try to engage the AC) |
My issue was the relay
First time in 30 years of car work I had a relay fail. If your ac fans on the radiator come on but the compressor clutch does not engage, swap the two relays. If your fans stop but your clutch now engages, then the relay is bad. Do not run it like this as it will overheat. I bought a relay at autozone and even though it was not as tall as the original it worked.
|
Originally Posted by OldSchoolScott
(Post 1484414)
First time in 30 years of car work I had a relay fail. If your ac fans on the radiator come on but the compressor clutch does not engage, swap the two relays. If your fans stop but your clutch now engages, then the relay is bad. Do not run it like this as it will overheat. I bought a relay at autozone and even though it was not as tall as the original it worked.
|
Originally Posted by doctor J
(Post 1423563)
Let's do this
plug connector back remove the ground wire from compressor (yellow arrow) https://cimg8.ibsrv.net/gimg/www.fit...04ab3c265f.jpg attach one end of 3 feet wire wire to this ring connector attach other end of this wire to the positive probe of voltmeter or test light (preferred) connect negative lead to the good ground route this 3 feet wire away from the belt and fans start the engine and turn a/c on the light should be on (not very bright) if clutch circuit is not interrupted (voltmeter will indicate 12 volts in this case)
Originally Posted by ezone
(Post 1423586)
Center wire is for the clutch field coil. The two outer wires are for the thermal protector--- which must have continuity, and the system cannot operate if you have the compressors 3 wire connector unplugged (fans will not even turn on when ou try to engage the AC)
If I have ground, then applying 12v to the center pin should get the clutch to engage? Am I reading it right that I'd need to short the two outer pins? Seems like just direcly using a battery or power supply would be my best bet to test it. |
| All times are GMT -4. The time now is 03:07 AM. |
© 2026 MH Sub I, LLC dba Internet Brands