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I'm new here and hate reading through the forums, so forgive me. I have an 85 f150 w/351. {stock} I had an electrical fire out on the fire wall with my heater blower. I replaced it with one from a junk yard, hooked everything back up, the clip was burned but not the wires, so I put a new clip in. Ran it and checking the wires out to see if anything heated up....all was fine. About 2 weeks later....SAME THING. this time I knew where it was, unhooked the clips for the blower motor....truck runs fine, no burned wires....I'm lost. At the point of yanking EVERY wire out and re-wire the whole truck.
Anyone have any suggestions of what caused this?
Usually a fire around the motor area is caused by leaves and debris piling up inside the air duct. Beside the motor there is a plug looking thing with several wires on it. If you take it out of the duct, you will see little coils of wire on the underside. These are resistors for the speed control of the motor, and some of them get red hot when the blower motor is running. All it takes is a dry leaf to set it off.
yeah the truck was bought from a landscaper. When I changed the motor, and evap box. I cleaned out all I could reach. The fire was electrical, that smell is unique. I have noticed a few times, I have to "jiggle" my ing. switch to get the fan to come on. Liek I said in the 1st post, I am not seeing any melted wires in that area....
When I got my truck, it had been with 5 previous owners.
The heater box was almost totally filled with leaf debris. It was within an inch of the fan speed resistors.
I cleaned it all out and back-washed the A/C condenser, and replaced the heater core just for the principle of it. Cleaned every electric connection at the blower motor and the resistor pak.
You DID buy a new/rebuilt motor didnt you? A junk yard motor can be just as bad as the one you take out.
Anyway, my truck has a helluva heater and A/C now. The previous owner just told me that the heater was burnt out. The motor was replaced several years ago.
Ya know, after seaching through this site, the one I got WAS from a junk yard, I got curious and took off the plug to look at the resisitor...man that thing was FULL of crud. Taking the shopvac to it this weekend and ordered new resistor/lug for it
I figured that you would find leaves or debris in your heater box if you looked. If you will serch for tips and tricks in the serch engine in this forum you can read a write up on this problem and check out other things common to these trucks there also. Any more questions feel free to pm me agiain. Scott