heater switch melting

[seas]

I have a 99 Wrangler 4.0 with AC. The problem is that heater control switch and the vent control switch both melt down. Every year(around Decemeber)I would lose high speed first. That is when it starts to melt. Soon after, all speeds are lost. When the switch cluster is removed, you would notice how everything is melted. Four trips so far to four different dealerships and none can determine what the exact problem is. Every trip seems to involve a replacement of the switch cluster and blower motor which does correct the problem, but only for a year. There must be something else going on that I am melting this stuff......Please help!!!

[fredjacksonsan]

Wow; sounds nasty. I'm not an electrical guy, but it sounds like there is a bit too much voltage flowing into the system. Do you have the correct amperage on your alternator? How about voltage regulator; have the dealers checked that?

Sounds like they're treating the symptom rather than finding the underlying cause of the problem. You might want to try a reputable auto electronics shop, they may be able to trace the voltage condition.

[JDPascal]

Ask the shop to give you the old blower motor. you can then check the blower motor for tight bushings or for shorted windings. It is high amperage that will melt the switch.

Do you live where they use a lot of salt on the roads?? that might work its way into the motor bushings or other places and cause problems.

You could probably figure out how to connect a digital ampmeter in the circuit and find out what the real draw is on the old one and compare it to the new.

One other thing to check is the heater motor resistors. There might be something there that is causing a repeat of the problem.

JD