Hello all,
I have an 88 full size bronco that melts the plastic off of the fuse for the hvac blower motor. It doesent pop the fuse just gets hot enough to melt the plastic . I pulled the motor out of its houseing and hooked it up to the battery and it ran fine but when i re-installed it its making a noise and still melting the fuse.
any ideas?
thanks
c-dubb

 

How many fuses have melted now?

 

I looked into this a bit. It seems that as the bushings in the motor wear, it spins too fast, drawing additional current and overheating the wire before blowing the fuse.

 

so it might still be the fan? i wonder how i could find out without buying the fan first.
thanks
c-dubb

 

Along with the blower motor there is a relay that turns it on and off, and a small resistor bank to limit the current going through the motor at each speed. There is a good chance that resistor bridge may have a short in it somewhere which would raise the current, but not enough to blow the fuse. One of the connectors to your motor is the relay and the other is the resistor bank. If you don't have a shop manual to refer to, you may be able to get the troubleshooting test from a mechanic to do it yourself. As long as the blower works that's not the problem.

As for the noise, check your installation. The motor is difficult to get in and is a snug fit in the duct. If it is slightly out of line it will rub and make noise.