1990 Firebird Formula. Long story short, I have a melted fan control (see picture). I have checked for shorts to power and ground using ALLDATA schematics. I'm a dealership tech, but we really don't get these older cars in anymore and no one around really has any clue why it burned this one specific section without any damage to wiring or blowing a fuse. Has anyone experienced this?

 

That is very unique. Do you know which setting that one is?

This probably isn't it, but I would make sure to check all the ground for the system to make sure they are grounded well though. I know that my blower motor ground wire was poorly grounded (either a packrat chewed it partially or it got damaged some other way). My blower relay went out a couples times over the course of a year and eventually the wires decayed. I think it had a strain on my blower resistor also. I eventually fixed the ground when I pulled my motor for maintenance.

Potentially a poor ground somewhere would cause high resistance and that was the weakest part for some reason?

 

I will check this. Thanks for the input. Also wondering if the blower is failing, causing excessive current draw. I agree with you. This may have just been the weakest part of the circuit.

I am also wondering if there was an internal fault in the control assembly.

 

If the blower is original I would think it would be close to failing. I think every car my parents/brothers and I have owned all had the blower motors fail. On my dads truck (99 yukon), the blower motor was going bad which did cause damage to part of the wiring eventually.

I suppose the control assembly could also have been faulty, but I would think that would be a somewhat unlikely situation unless it was actually damaged before from removal/installation by previous owners.

 

I've had my car since 1992, even back then when brand new I had experienced some melted connectors, that look like they may be related to HVAC control. Not enough to cause anything to stop working, but noticeable.

It wouldn't necessarily have to be a short would it? Something could be causing it to draw too much current and heat up in that area?? A loose or dirty connector could cause high resistance, and thus heat build up.

 

I know this thread has been dead, but I am getting back into this issue now that I have located a replacement HVAC selector.

That is the high speed fan terminal. It has not been touched, so terminal spreading is doubtful. Also all other terminals look clean. I have not performed a terminal drag test but everything is visually okay.

I may just go ahead and throw in a blower motor and resistor and periodically check my connector, though I'm having trouble locating a replacement connector.