Problem with radiator fan circuit.

[phantomcow2]

My 93 LX 5speed's radiator fan never comes on. To confirm it isn't working I jumped the female pins on the thermostat connector. THe fan STILL doesn't turn on (I believe it should).

Please look at the following picture of my relay location (in fuse box). I labeled the four terminals A, B, C, D.



http://postimg.org/image/3ux709qnz/


Using my multimeter and jumpers I tried everything I think could be beneficial for diagnosis:

- Jumping pins on thermostat connector makes continuity between A and C.
- Jumping pins on B and D turns the fan on.

I tested voltage from the battery to each of the four pins.
Pin A: 11v
Pin B: 0V.
Pin C: 11v.
Pin D: 12v.

What is wrong with my unit? I tried the power window relay, which is the same size and fits right in, and it does not work either. My power windows DO work.

[sonikaccord]

B and D are connected to the fan and the battery, respectively.

Your fan works, to check the relay while it's in the circuit there is a wire you can ground on the fan timer circuit and the fan should kick on. I can't remember which wire at the moment, I'll have to look it up. Your coil sounds like it's not being triggered.

[phantomcow2]

B and D are connected to the fan and the battery, respectively.

Your fan works, to check the relay while it's in the circuit there is a wire you can ground on the fan timer circuit and the fan should kick on. I can't remember which wire at the moment, I'll have to look it up. Your coil sounds like it's not being triggered.

Do you know how to tell if my relay is getting power in the right pins? I think the relay is good since I plugged it into the power window slot with good results.

[EsperHamid]

test the fan switches resistance, check page 16-109 in the repair manual

[phantomcow2]

test the fan switches resistance, check page 16-109 in the repair manual

Relay confirmed working. THe problem is that I am not getting the 12v necessary to activate the relay. No idea why.

In the interim I made my own circuit consisting of a relay, coolant temp switch, and fuse. Now it works.

[dahubby]

you may have a short in the actual temp switch. It may not be sending the proper voltage to the relay.

[phantomcow2]

I noticed i'd get half a volt when I manually shorted the temp switch connector. There must be some power supply failing upstream. Oh well.