Air Conditioner noise

hawkeye52

2002 T&C w/3.8L V-6 & 107,000 miles. Bought it new and it has been relatively trouble-free. BTW, factory-original brakes were replaced today!

Today when A/C was switched ON, a loud click-click-click-click-click noise was heard starting about 30 secs after it was switched ON and lasting about the same amount of time after it being switched OFF. Could this be the A/C clutch cycling?

Any other ideas?
Thanks!
- H52

srs_49

Was the sound coming from under the hood or from the passenger compartment?

A/C clutch relay, which I think is under the hood, maybe in the fuse box.

hawkeye52

Thanks for your reply, srs_49.

The click-click-click noise is definitely from the engine compartment, but from the vicinity of the compressor (which I cannot actually see). If the A/C clutch relay is in the fuse box, that would put it on the opposite side of the engine compartment....

- H52

srs_49

If you want to try to isolate it, disconnect the lead going to the compressor or pull the compressor fuse and see if the noise is till there when the AC is turned on.

Another thing you could try is, with the lead to the AC compressor disconnected and the engine running, apply 12V to the compressor from a batter charger or from the battery (with an appropriate sized fuse in the line for protection since this will bypass the fuse in the fuse box) and see if the noise is still there. Obviously, be very careful using this technique because 1) the engine is running, belts are turning, etc and 2) you are connecting directly up to the battery which can puts out many hundreds of amps of current in the event of a short.

A battery charger on it's lowest range would be my preferred method.

hawkeye52

I pulled the A/C clutch relay... turned on the A/C... no click-click-click noise.
Put the relay back in... started the A/C... and the noise came back.
So it is definitely related to either the clutch or the compressor.

Is there any SIMPLE way to pin-point further?

-H52

srs_49

If you have a voltmeter, you could connect it to the lead going to the compressor clutch; see if there is a voltage fluctuation that is in sync with the click-click noise.

Since you found the AC clutch relay, you could also just try jumpering across the contacts that would energize the clutch. This is pretty much the same as the second suggestion I made.

What I don't know is if there is another relay or solenoid inside the clutch itself.

hawkeye52

Took the T&C to 3 different A/C shops today. The verdict was the same at all three: the compressor is shot.

I'm having it replaced on Friday. Then, hopefully, we'll be able to determine if it died of old age (it's the factory original with 107,170 miles on it) or for some other reason.

Srs_49, thanks for taking the time to help me diagnose this.

- H52

srs_49

Thanks for the update. Let us know how much it's going to cost to replace.

If it's any consolation, I don't mind having things like that replaced so long as I'm pretty certain that's what the problem is. You did enough troubleshooting to be pretty sure that's where the problem was. The A/C shops just confirmed your diagnosis.