Quote:
Originally Posted by Zacharias
On the blower: I was recently reminded that apparently, a blower motor with well worn brushes may not come on except on defrost, because only on that setting does it get a full jolt of power (max speed). (I am passing on what was reported to me, I am not the owner of that factoid  .)
Have you tried applying 12v directly to your blower? |
That is my experience. My '79 has a kind of sad, squeaky blower that works OK but sometimes won't start without being hit with a jolt of Defrost first. It matches with what I've read elsewhere.
A 12v hit to the blower is the best way to eliminate it as the problem. While working to get the ACC in my '85 working I put 12v on the blower as one of the first steps. It worked beautifully. I then tested for power at the blower plug and found none. With just those two simple diagnostic steps I was able to determine that my main issue was a lack of power delivery to the blower, somewhere along the chain.