Please confirm my auxiliary fan diagnosis

[clydesdale]

When I jumper the wires on the themoswitch connector, I get the fan to run. BUT IT ONLY RUNS IN THE SAME SPEED. I am not sure if it is high or low, but I assume high. But, putting a wire in both the low and the high speed terminals, causes the same speed to be triggered.

When I hit the a/c button, I get nothing.

When I jumper the high speed relay and the low speed relay, K1 and K6 at terminal 87, I will then get the fan to run when I hit the a/c button.

It appears the low speed fan is not working. So, that makes me think the low speed resistor is the culprit. What do you think?

[Jaxx_]

i agree. the resistor is on the fan and is the white block. check resistance accross it or for damaged wiring. it's probably an open circuit.

[jlevie]

If the fan runs at the same speed, regardless of which contact you jumper in the thermo switch connector, The speed resistor or a wiring fault will be the problem. You may find, once the grill is off, that the speed resistor has been bypassed.

[clydesdale]

When I wiggle the wire, right where it inserts to the resistor, the fan works. Are the wires screwed into the resistor? Is it worth trying to fix or do I just need a new resistor. It does not appear to be where it attaches to the car wiring.

[jeffnhiscars]

When I wiggle the wire, right where it inserts to the resistor, the fan works. Are the wires screwed into the resistor? Is it worth trying to fix or do I just need a new resistor. It does not appear to be where it attaches to the car wiring.

The factory installed ceramic resistor has a tab & screw and the wire has a round lug. All this will be clearly visible so just tighten the screw. Sounds like you have the replacement style which came with pigtails that you crimp connect. If thats what you have and the wire is shorted where it goes in to the resistor you need to bypass or replace it. They are not serviceable.