A/C Fan Switch Wire Plug??

[Luis_gz06]

Is it normal for the fan switch wire plug to heat up? Everytime I turn the fan on, I touch the wire plug on the back of it, and it gets real hot sometimes. What could it be? Thanks!

[JimKshortstep4x4]

It is not normal for the wire to heat up. You did not mention if the fan is on high or not but if the wire heats up with the switch on high then I would suspect that your relay is not working properly.

Jim

[Andy4639]

Heating of a wire is a sign of bad connections, parts or wires just being old. Are all the above. Parts and connections should be checked and fixed first then check wiring. Most of these old trucks have seen some rough times.

[Longhorn Man]

I agree with andy 100%. Your plug that is getting hot has a bunch of resistance. Warming up is normal, but hot is excesive.
I would unplug it, clean/replace the switch... then take the plug apart... I'd do it one terminal at a time, and clean each wire up. Put the wires back in the plug and give it a good glob of dielectrical grease.

[leddzepp]

Easier just to change your resistor and relay switches. They are relatively inexpensive and can be purchased at most major auto parts stores. That way you have brand new parts and therefore eliminate the possibility of those things being the problem. The relay is usually the culprit in this case, and luckily is the easiest thing to replace. Pop out your glovebox cardboard (if its still there) and you can easily access the relay switch on the side of the A/C box, next to the passenger kick panel. The resistor is a little more difficult to access, and you have to remove the "S" duct from the diverter box to get to it.

[Longhorn Man]

the heat will be at the resistance. There's no sence swapping out parts that aren't needed.

[leddzepp]

For 10 bucks, I say swap it out. They are 40 year old parts. Besides, when I had this problem changing the relay solved it.

[neonlarry]

These trucks do have a habit of frying the heater switch, thats why the factory put in a relay for the high speed. It wouldn't hurt to put in relays for the others two speeds.

[Hook'em]

I have replaced my a/c blower switch at three times in the last four years. It always shows signs of heating up at the plug. I have changed the electrical fittings that plug into the back of the a/c controller, but to no avail. Maybe I need to changes the relay. Otherwise, I just keep an extra blower switch handy.

[leddzepp]

I live in So Calif and run my A/C constantly, and have never had a problem with my fan switch. Change your resistor and relay and you will eliminate the problem.

[Andy4639]

What I was trying to get across was in any electric system heat is a sign of something wrong weather it be the part or the wiring or a connection. Start by cleaning up what you have first...cost is just a little bit of time. If the connections aren't the problem then buy the parts you need to complete the circuit.
I say this because of my other hobby. Electric golfcarts and a wire terminal heating up is usaully a bad connection. A controller ($300.00) or other parts are expensive to just replace. Most of the time it's just a bad connection.

[Luis_gz06]

Thanks alot for the info guys. I replaced the switch, and no more heated wire. But I will still replace the relay and resistor just to have everything new, and use it with more confidence. Thanks again all, Luis.

[DavesRide]

I agree with Longhorn Man and Andy both. As a Chevrolet tech I replaced many a melted wire due to a poor connection. Especially on the ground side. Even in 2005, Chevrolet couldn't overcome the laws of physics and the heat a poor connection can produce. If you wait long enough like my poor old truck has waited then it gets it all replaced as it all will melt.

[neonlarry]

Although I agree with all of you on bad connections causing heat from I²R loses. That may be part of the problem here but under design (read too cheap) by GM is also part of the problem. Same thing for the headlight switch and dim headlights.