Test if Fan Works?

[Bills86e]

Originally Posted by JNCoulombe

Since the circuit diagrams that I have seen only show the ECM (DME) as essentially a black box without imput from the ECT it is hard to know how a bad ECT might affect the system. However, jumping between the brn and blk/grn wires at the radiator temperature switch with the ignition switch on will run the low speed fan when the car is cold which suggests that ECT input is not necessary.

Mine when jumping, the the brn and blk/gr at rad does NOT turn fan on, and is my complaint. The fan however does work on both speeds as post 16
proved. I have yet to get voltage thru blk/grn wire.

[JNCoulombe]

I meant that normally jumping the brn to blk/grn wire will turn on the low speed fan.
Try using a jumper wire from the switch to the relay as I previously suggested. You should at least have a reasonably functional system if that works.

[Bills86e]

JNCOULOMBE
I do not want to jump this thread, can you look into my thread
at No low speed fan signal? Thanks for any help!