Blower motor Darlington transistor HELP

There is only 3 ways the blower can run with ignition off either the relay is shorted, the transistor is shorted or a short on the PCB or wiring.

Use the trusty DVM on Ohms and measure from the Darlington case to ground (green wire) and do the following looking for the short to disappear.

1 - Check the PCB where you soldered for a slither of solder shorting the tracks
2 - Remove the relay
3 - Remove the screws from the transistor

warjon
I would like to thank you for your great help , after reading your post I was able to find my problem .
I had made an extension harness to test blowers before installing them using 2 jaguar male and female PM5 connectors .
I did not pay attention to polarity of the wires and reversed them in process of making my harness.
I corrected the polarity on my extension harness and tested the blower , I was the happiest person in southwest Virginia when I did not hear the blower running when the battery was hooked back up.
I owe you a big time for your help.
my repair was successful however the test method was not so much.
Have a great day .

Hi Mike
finally fixed the problem , if you read the my last post you will know what was the problem.
thanks again

So easy to do, I have been repairing electronics for over 30 years and I still make dumb mistakes.

Good to hear you have it fixed now.

1 Like