Cooling fan is not turning on. It does not seem to be the fan motor, relay, OR the thermoswitch. Here is what I know:

-Not getting any voltage at the fan
-Fan motor works when directly supplied with 12 volts
-Jumping the thermoswitch does not turn on the fan, or provide any voltage at the fan connector
-Switched relay with known good relays, jumped the thermoswitch, fan still does not turn on

-Reading the voltage on the signal side of the relay, it only reads about 3 volts when I jump the thermoswitch

So that is my main question, should the ECM be putting out 3 volts on pin A12 to the relay? Or is it supposed to be putting out 12 volts?

Thanks!
-Nick

 

I was playing around a little more:

Measuring from ground to the 2 signal pins going to the relay, one pin reads 12 volts, one reads 0.4 volts, with or without the thermoswitch jumped.

But if I measure between the 2 signal pins, I get 0 with the switch open, and ~3 volts with the switch jumped.

I am pretty confused. One of the signal pins should be ground, shouln't it be?

Any ideas?

 

Test fuse 13.