Hello I have a 2005 TL, recently, the ac clutch started to not engage, causing no ac of course. I have checked the fuses and relays, all is well there. When I turn the ac on, there is nothing engaging or clicking, but the engine seems to labor more, so I guess what I’m saying is, where do I go from here. The ac was working just fine a week ago. Is there any other connectors I should check?

 

If you are sure the AC Relay and fuse are both fine, check the actual connection to the compressor first, though it could be a bad compressor clutch. Either the pulley may be stuck or the stator for the AC may be bad. Try tapping on the AC pulley while it should be engaged to see if it's sticking. Obviously not with your hand or anything that could get caught in the belt.

 

If your coolant pressure is below a certain level, the a/c clutch will not engage (see yellow in attached image from SM)

You will need an a/c manifold gauge to check pressure.

 

I think you meant Refrigerant, not coolant. But yes check your refrigerant, if its low the clutch will not engage. This could also mean you have a slow leak somewhere. If you top it off correctly and still nothing, must likely your stator/clutch is bad. Ive gone through 2 stators so far, 3rd one was the charm havent had an issue yet. Best bet is take it to a professional to diagnose.

 

i suspected I had a leak, but not very large. I checked the ac relay with my multimeter. 14.x volts on point 1 and point 4. That means that there should be power to the clutch. The jumper wire didn’t get it to engage. Could the pressure switch be blocking power ever after the relay? I’m a pretty competent mechanic, but some of this ac stuff gets confusing really quick.

 

Take a look at the right top of this image. AC relay will have constant power on two of its pins (when key in ON position). Relay's coil is controlled by ground (by the computer).
Pressure switch is not here. It simply feeds the info into the computer. If relay gets power on pin #1 and #4, and ground at #3, then it should send power to the compressor clutch.
Use test light, as voltmeter might give you wrong results. Probing this relay pins with test light won't damage anything.

Of course the best way is to test for power as close to the clutch as possible.

If clutch went bad, you should be able to find just the coil / clutch on ebay / Amazon. Cheaper than whole compressor and might be able to leave refrigerant in to replace it.

 

Ok, so after some more digging. Here’s my symptoms and my diagnoses. All of the electrical checks out until at leastthe connector to the compressor itself. (The connector that plugs into the compressor reads 14.x volts) that means the the clutch should be getting power. I think that it needs a new clutch, but before I order it, I’d like to know if the wire that runs from the compressor to the electrical input connector from the relay has a plug into the compressor. I say this because I left out one part of this scenario. A couple days back on my lunch break, my rear sway bar link went out and I fish-tailed on a country road on to a grass uphill mound. Everything appeared to be fine and I backed off of it. Could the connector that goes directly into the compressor undo itself? Or am I just hoping for the best while needing a new clutch?


ps, is there a ground wire on the compressor somewhere, bc that could have came loose too.

 

(a) I think the connector to the clutch is the snap-on type (see attached image).





A few posts back someone recommended you tap the clutch. The following video explains how that works and why. He taps the clutch at the start of the video. If this is your problem, the fix is usually easy and cheap (just replace the spacer).


(b) I think the compressor connecting to the engine provides the ground but I'm not 100% sure.

 

The stator/coil ive seen on ebay cost as much as a new replacement compressor. I would just get a new compressor and call it a day.
Anyways, the wire from the stator/coil on the compressor has 2 wires, one directly bolts on to the compressor (ground) and the other is the grey plug (power). I have a power probe tester which helped me a lot, I simply connected my probe ground to the engine and connected the grey plug to power probe tip. Send power to the stator and should hear the clutch click. If the clutch doesnt click/engage when you send power the stator is toast.

 

Sorry OP,

I linked the wrong video. In the video I sent, around the 18:00 to 18:30 minute mark, he explains that for that car, the “gap issue” that he diagnoses by tapping the clutch may not be fixed with a simple shim. It appears that on that car the air gap varies due to “worn spring tension” or “whatever”.

In the video I am linking below, the air gap issue that he diagnoses by tapping the clutch IS fixed with a simple removal of shim. At the 12:30 mark he diagnoses the air gap problem. At 20:00 he removes the existing shim which solves the problem.


Sorry for any confusion.

 

I ordered a new clutch and coil. I tried tapping it and even made sure that the plugs going into it are secured and clean. Still nothing out of it. I know I’m getting power to it, the clutch must have just gave out. Is it normal for them to give out at 123k? My last had 170k and the compressor worked good as new. That being said, it is a Chicago Car meaning rust and such is an issue. We’ll see if this clutch works. I believe it will though.

 

Just went through this on my 04 TL. Checked all the above you mentioned and then when adding Freon to the charge port I realized the schraeder valve was leaking. 5 minutes later all Freon was gone. $5 for a new valve and can of freon and were back up and running.