hot air conditioning fan switch

[Steve 82SC]

The car in question is a 82 SC. All air conditioning system is stock, with parts having been replaced as needed. The compressor is still the original York and the system, with R-12, blows very cool....not as efficient as a modern car, but OK for what it is.

I recently cleaned up the thermostat switch because it seemed to not be capable of turning the compressor off. Everything went OK, but when I was running the system without the console in place with the thermostat and fan switches not yet in place, I noticed that the 3-speed fan switch was quite warm, bordering on hot.

Is this normal or do I have some sort of issue with the switch?

Thanks,

Steve

[Steve 82SC]

Anyone?

[rick-l]

The only way the switch would get hot is if the contacts are dirty. The switch contacts are supposed to be a very small resistance. P = I^2 * R ~ 0.

If they get dirty and the contact resistance goes up the power dissipated is no longer insignificant.

If it feels hot I would bet simple contact cleaning is not going to fix it.

[DonMo]

Same thing happened to me, I redid the crimp connections, heat all gone.

[onemark]

Hi Steve,
Mine got really hot just before it failed. I think the contacts inside built up a bunch of resistance from arching. The replacement that I got (from our host) had a slightly different pin-out configuration that I was able to figure out with meter.
All fan speeds work well now....if only it would actually blow COLD!
:-)
Mark

[D911SC]

I just had my shifter bushings replaled and the mechanic said the switch was scorched at the back. I noticed it had become quite hot as well. I am replacing mine as I assumed it was on the way out.