When I slide my blower speed control over, the blower motor starts up moderately fast, then within a second or two slows to a crawl.

I thought it was the logicon, so I pulled it out and resoldered all the connector leads on both the main board and the smaller board in the separate little black box. (Nothing on either board looked burned; all of the solder looked a-one.) This didn't solve the problem, but at least nothing was worse! (All the other functions of the logicon work just fine.)

If it was the thermal fuse on the power transistor plate, the fan motor wouldn't run at all, right? So the fuse is probably okay.

Can the power transistor have failed? If so, is this an item that can be picked up at Radio Shack?

I can hear the relay click, so it's probably okay, and when I applied 6 volts (as I remember... maybe it was 12) from a dry cell battery, the motor spun, so it's probably okay, too.

Any suggestions would be appreciated. I really need my defrost!!

 

I would suggest the thermal fuse. Mine clicked as yours did, and my motor spun when hooked to a 12v source. Doesnt hurt to try replacing it.

 

Thanks for the reply.

Every time I slide the fan speed control to 'off', and then over again, the fan starts to blow before it drops off in speed. If the thermal fuse was blown, there wouldn't be any juice getting to the fan motor at all, right?

But I'm going to pull the fan & motor assembly out to try out a rotary switch (taking current from the lighter), so I'll take a look at the thermal fuse.