hey,

I recently picked up an '88 b250 with a 318 and the super long windowless body for next to nothing.
Runs great, drives great, takes up a parking spot and a half, even shifts into reverse most of the time.
However, the blower fan works on LOW speed only.

In my experience, if you only get HIGH speed, then yer (rheostat? regulator?) ...whatever the voltage step down device is called... is shot.
So I pull it out of the firewall behind the glovebox, and it looks just fine.

So... is the problem with the relay? or mebbe something else?

Is there any way to test the relay to definitively confirm or deny that this is the source of the problem?

Much thanks in advance,

Alex

and, oh, yeah, Happy new Years!

 

Resistor pack can be blown and still look good. Since you only have low speed then I would replace it and the relay as well. That should get you all the speeds back.