A/C and fan speeds

[teleski]

Can you clarify; turning the AC on switches the relays but the fans do not run, i.e. if you walk to the front of the car they are not running?

I ask because I have always assumed that the resistors fail by presenting an open circuit and you can verify their integrity by measuring their resistance < 1ohm between pins 30 of the low and high speed relay sockets. I have yet to let my car run long enough to have the high speed fans kick on. I should probably do the jumper trick to at least hear what they sound like.

[thom4782]

I'll be glad to clarify.

I've preformed several tests. Last night, I turned on the A/C with the engine cold. I could not hear either fan operating at low speed. I waited until the refrigerant pressure triggered high speed fan operation, both fans operated. So I know at this point, both fans work and the fuses are OK.

This morning with the engine cold, I pulled out both low speed relays and jumped them to see if the fans cam on at low speed. They did not. I repeated the test by turning the ignition on. No operation. I started the car with the AC off. Still no low speed operation. Finally, I turned on the A/C. Still no low speed fan operation. When I removed the high speed relays and jumped them, the fans operated at high speed

My understanding is that with then engine cold and the A/C on, jumping the low speed relays will start the fans. In my case, this didn't happen.

If I had a multimeter, I would try measuring the resistance between the 30 pins on the high and low speed relays. But alas, I don't.

BTW: My understanding is that both fans run a low speed when the A/C is on. If I'm wrong, I'd love to hear about it bcause it could be that the fans only operate a low speed when the coolant gets hot enough. If that's the case, then my test wouldn't not have worked because the engine wasn't up to operating tempereature for the thermostat to turn the fans on.