blow motor fan only goes on high

[bluesboyst]

My marauder's blower motor only goes on high... is that the resistor mounted on the firewall which replaced twice already?

[SilverPhoenix]

Most likely. Mine was doing the same; replaced it 2 months ago.

[bluesboyst]

Thanks.. i replaced it out 2 years ago with a Ford part too... geez....

[fastblackmerc]

I can repair yours. PM me.

[pantheroc]

I have a theory on why these burn out, but need to ask a question. Do you use Max AC with fan set to less than HI? I suspect the transistor is not getting cool outside air across it, per hvac diagrams, thus it is overheating. When normal AC is selected, outside air is flowing across the transistor.

[SilverPhoenix]

I've heard that the failure is caused by poor quality solder being used at the solder points...

[Black Terror]

Mine was Solder joints, resoldered with better solder and lasted until I sold the vehicle. That is the repair that Jim uses most of the time.

[fastblackmerc]

Mine was Solder joints, resoldered with better solder and lasted until I sold the vehicle. That is the repair that Jim uses most of the time.

I use solder containing lead. The solder used in OEM units has to be RoHS certified which means it has no lead in it. Lead is what makes the joints flexible and not prone to crack or fail. I also add a copper wire at a certain connection.