Intermittent Defroster Blower

[robm]

Twice now, the defrost blower has suddenly stopped working. This is not a resistor issue, I have dealt with that one a few times. The blower suddenly goes from working on all speeds to not working on any speed. This is on a 1993 Loyale 4WD, 280,000 km.

 

The first time, I poked and pulled a few fuses. All were good. When I tried the blower again, it worked.

 

The second time was a lot scarier. It failed while I was 20 miles from home in a blizzard, and had to crawl the last bit with the windshield wipers scraping over the ice. This is NOT a safe way to drive, given the road is so snowy I can hardly see where it is when the view is clear.

 

Poking the fuses didn't work this time. I got out the Haynes, pulled off the panel to access the blower, and was ready to start probing with the DMM and it started working again. Very strange.

 

The Haynes schematic is not very good, as it covers vehicles with A/C, and I don't have A/C, so the diagram has lots of very confusing extra stuff on it.

 

Is there a blower motor relay on my car? If so, I wonder if it could be the heat affecting it? Maybe it gets hot and stops working. Where is the blower motor relay?

 

I hate intermittents that fix themselves....

 

Thanks,

 

Rob.

[pixO]

Here's a Blower Motor Wire Diagram:

 

http://www.pixogen.net/usmb/1993%20Loyale%204WD%20Blower%20Motor%20Wire%20Diagram.pdf

 

I'm not sure what all depends on the black fusible link (other systems would be dead if it were burned out/intermittent), but I'd check that wire for continuity off the car or voltage while on the car & running. Check fuse 1, 2 and 12 for continuity (or a visible inspection at the very least).

 

It looks like there is a relay. It's located under the left side of the dash, behind the instrument cluster:

 

Edited December 6, 2008 by pixO