Aux fan never runs, compressor stays on and possibly related unplugged cable?

[CarterH]

My aux fan ran when I first bought the car but at some point in the last year, it stopped ever running. I never had any temp issues so I never did anything about it. However, my AC compressor broke a few months ago and the cause according to my mechanic was that it constantly ran and never shut off. It's been replaced since but now I'm wondering if the same issue is happening again, since the compressor clutch seems to run constantly when the car isn't moving. It does however cycle on for a few seconds then off for a few seconds when I'm driving at a low enough speed that I can hear it clicking. Is that fairly normal? Having it run constantly at the lights feels really wrong. It does blow nice and ice cold though and the car never struggles when it's running.

EDIT: Remove the part about the cable, I managed to trace it along with a torch and found it was just a wire for the horn. D'oh. All the fuses also check out but I don't know how to tell if a relay has gone bad though.

[Layne]

The compressor is more than capable of running continuously. That should cause your evaporator to freeze up and stop the interior airflow though.

There is a high pressure shutoff switch, so poor outside airflow can't cause any damage. First test the fan switch by jumping the connector and seeing if the fan kicks on. The fan switch is in the radiator and has 3 terminals. The middle one is ground, and the two others are the two fan speeds. Jump the middle one to either side and the fan should come on. It's common for the low speed to go out because it uses a resistor to lower the voltage and the resistor burns up. It's located on the electric fan itself for cooling. Relays can also be a problem, or power to the relay either the main power circuit or the relay control circuit.

[ross1]

All the above plus check that the fan isn't seized up which is pretty common.

[CarterH]

The compressor is more than capable of running continuously. That should cause your evaporator to freeze up and stop the interior airflow though.

There is a high pressure shutoff switch, so poor outside airflow can't cause any damage. First test the fan switch by jumping the connector and seeing if the fan kicks on. The fan switch is in the radiator and has 3 terminals. The middle one is ground, and the two others are the two fan speeds. Jump the middle one to either side and the fan should come on. It's common for the low speed to go out because it uses a resistor to lower the voltage and the resistor burns up. It's located on the electric fan itself for cooling. Relays can also be a problem, or power to the relay either the main power circuit or the relay control circuit.

I'll assume this is the plug you're speaking of right? I can see it has three wires and the brown ground wire.

radiatorcables.jpg

I'm not sure where the resistor is exactly. When you say it's on the fan itself, would it only be accessible if I took the front grill off? I'm willing to bet it's a burnt out resistor. I'll also see if the fan can move freely or if it's seized up like ross1 said.

[Layne]

That's the one.

The resistor only effects low speed. High should still work if it gets hot enough to come on. Yes, probably need to remove the grille to get at it.