Automotive Air Conditioning Information Forum

Hello. In my 2009 Altima, the blower and everything works and the AC light comes on when you push the button, but no cold air and I can visually confirm the clutch is not engaging. I checked the AC fuse and it is good and there is power to that fuse block when I turn the AC on. I pulled the harness at the compressor and I am not getting any voltage when the AC is on. What do you recommend I do next? Do I need to first make sure the system is charged so the pressure switches are not causing the clutch to not engage? If so, would I have to buy gauges for that, or do you know of some auto parts stores that test it or loan the gauges?

This stopped working in the winter and I remember it being pretty cold and working fine last year so it seemed to just stop all of a sudden. If the system is charged, then does it sound like probably a bad IPDM (since I think the relays are built into that)? Any other advice as to what I should test next?

You may be low on refrigerant. The first thing you need to check is the refrigerant. Recover the charge and see if it is low. Properly recharge and go from there. I think you can get a set of gauges from this site.

I found a local auto parts store that loans out the manifold gauge set. Can you just hook those up to test the pressure? The instructions I read say to have the compressor running but I can't do that.

Verify the proper amount of refrigerant.

You can put the gage on the car- if it reads less then 47 psi with engine off and it is above 70 degrees out- then you have an extremely low charge issue- compressor should come on when pressure builds when you add refrigerant- just that you don't know how much to add- and if gage reads zero psi- you have a massive leak. Best way to handle is to recover and weigh refrigerant you have in the system- compare that to the under hood sticker that states the refrigerant requirement- then decide how to service.

Just reporting back on this, I verified 80 on both sides with it off so that sounds like plenty. It must be something in the wiring, a relay, or sensor then, right? I really don't know exactly where everything is located so I am probably out of options. Any other suggestions or does it sound like I need to bring it in?

You need a service manual to trace the signals.

Hello again. Just to update this, I was totally wrong the first time. I ran the IPDM self diagnostic test and was getting voltage at the harness into the compressor when I had it unplugged. I also just tested that harness again with the engine running and the AC button on and am getting voltage. I must have not had the voltmeter in far enough the first time. So this is a compressor problem and it needs to be replaced, right? And since I don't have tools to recover or refill the refrigerant myself, I can't really replace it myself can I?

Went thru a similar experience and got the following advice from forums;
1) With engine off try and turn clutch plate by hand. If it doesn't turn your compressor is most likely busted.
2) You say you have power to clutch but also check that you have ground in the other wire.
3) Disconnect wires to clutch at compressor connection and test resistance through clutch (coil). Should be roughly 2 to 5 ohms with infinite or very large reading indicating bad clutch coil and same below 2 with near 0 = shorted clutch.

If clutch resistance tests bad there is the possibility you can have the clutch only replaced but there must be some access room to do the work, you have to find a "clutch kit" for your car and finally must find a shop willing to do the clutch only as most will want to do the whole compressor (for profit AND some other valid reasons.
Good luck.

Hey thanks for the advice. I went out and checked what you suggested:

1) I was able to turn the clutch plate by hand.
2) I did check the ground in the other wire so that is good.
3) I fumbled around for a bit trying to test those two pins at the clutch and am fairly confident I got the test probes on both of them eventually and was getting no continuity between the two (getting the OL).

When you had this problem, did you fix it yourself or have a shop do it? I have seen some videos on it and it looks like it isn't too difficult to access once you remove the wheel, but it does sound like the bolt is difficult or impossible to remove. Was wondering how the bolt came out for you if you did it yourself. Thanks.