Rough Idle when A/C is On

I have a 97 Villager and whenever I turn on the A/C, the idle surges up and down about every 2 seconds.

Also, you can hear the A/C go on an off in synch with the idle surges (click click, click click).

Any ideas?

Thanks in advance.

I have a 97 Villager and whenever I turn on the A/C, the idle surges up and down about every 2 seconds.

Also, you can hear the A/C go on an off in synch with the idle surges (click click, click click).

Any ideas?

Thanks in advance.


Air conditioner Relay..whenever you hear intermittent clicks think some sort of relay switch...The clicks can be either the relay telling the A/C clutch to engage to start circulating the freon or the a/c clutch itself engaging and disengaging...your idle will have to go up to compensate for increased power drain from the compressor.

anyhow back to your problem..
it can be a few things like your refrigerent level is low, your a/c clutch is bad, a/c pressure switch, a/c cycling switch and/or power train module...
The a/c pressure switch(located on the compressor) has two functions it signals the a/c clutch coil and also manages the electric cooling fan
the a/c cycling switch (located by the accumulator) monitors freon pressure so to prevent the accumulator from freezing and signals the power train module which will then help in either engaging or disengaing the a/c clutch.


I would determine if you have a low level of freon, you can do this quite easily...get yourself one of those canisters of R134A with the gauge and measure the level..if its fine then the most you are out is an extra can of freon for next summer to start nice and cool.
If its low, then fill it and see what happens, if it is then fine then great, if not monitor the level and if it gets lower, have the system checked for leaks........otherwise, IMHO, it may just be one of the switch.the idle surge is just responding to the a/c signaling on and off

BTW, sorry it is the a/c pressure switch that signals the Power train module....anyways also look at the a/c relay itself

Thanks for all the great help. I am going to begin with your suggestion and (if I have to) move on up from there. I'll keep you all informed.

Thanks again.

is it normal for the compessor to run with the heater on?
mine just keeps right on ckicking the whole time the heater is on.