My coolant fans do not turn on automatically when AC is engaged so AC effectiveness is compromised when idling or moving slowly. Both fans turn on when coolant temperature reaches high enough temperature to call for their use but then both turn off when temperature is brought down even though AC is still turned on. Would this be a relay, faulty wiring or is there an override switch of some sort that forces the fans to turn on with AC compressor?

In hot climates, the fans will usually turn right on when you click the A/C button on, but when the temps are cooler, the fans won't turn on right away because the high side pressure is below the 'cuton' for the fans.

Let the car sit there with the A/C on high and watch the fans for awhile.

I looked up the wiring diagrams for this.....

There are actually 3 different configurations....with one relay, two relays, and another with three relays......

The one with three relays uses an inline resistor to the main fan, for low speed....this resistor can be bypassed by one of the relays to get full battery power, and thus high speed....there is also an auxiliary fan set up to come on when pressures(or coolant temp) get too high....

Main thing is, there has to be an"A/C on input" from the control head to the ECM to turn the fan(*) on...if there isn't , no fan......but there is a backup system in the form of pressure, and temp switches which will ground the relays.....

It could be possible there is an ECM problem, and there is no low speed operation(or as I said, no input from the control head)....as Mike said, the fans may come on later, as head pressure in the condenser builds up, and the lo/hi pressure switches close to turn on the fan(*).....If the ambient temp is low enough, just natural air flow could keep the pressure down in the condenser....

Where do you live? And what are the ambient temps when you turn your A/C on? If in Florida, and temps are 70-80'*, I would think that the fan should come on right away, especially at low speed......but if you have the system with an inline resistor and it is open, then there would be no low speed fan....

Like I said, there are three different coolant fan setups for your year vehicle....

check coolant fan operation without a/c on......just idle vehicle ....when temp gets to 200-210, you should have low speed operation, and only one fan on......then raise idle to 2000....when temp gets to 220+, then both fans should come on at high speed.....

If you are not getting a single low speed fan, only two fan high speed, then you know you have a problem with the low speed fan circuit.....

Thank you so much for the replies. I live in North Georgia and only acquired this car recently so it hasn't been particularly warm since I've owned it. Probably in the 70s when I first tried the A/C. Although the A/C is cooling, the compressor seemed to cycle on and off more frequently than I would have anticipated. When fans did turn on it was both fans at once so you may be right, Tech II, about it being a problem with the low speed fan circuit.

Under low load conditions, it is normal for the compressor to cycle.......could also mean borderline pressure also......