I have a 1991 ram 250 van and the blower switch keeps getting overheated and frying the switch. I need a diagram showing what fuses are what. Could the resistor on the firewall behind glove box be bad?

 

I'm on my second one as well. I notice the new one gets hot when left on high for any length of time. It's internal resistance in the switch causing the heat. I suspect it's just cheap switches. Though a high resistance connection between the wire and the switch (bad quick connect) would cause a lot of heat, too.

I doubt the resistors have anything to do with it. They are by-passed when the switch is on high. And they lower the current when the switch is on other settings. Lower current means cooler switch.

The fuse is just a piece of wire that melts when the current gets too high. It would have nothing to do with the switch getting hot.

 

It's more likely that the blower motor is worn and drawing more power than the switch is designed to handle.

 

Yeah that's what I was told last year and I replaced the motor but it still overheats. The resitor is the only thing I have not replaced.

 

I've taken my switch apart twice to clean the contacts of carbon, but not for several years now. The second time I bent the contacts so they increase the pressure and polished them to a greater degree.
The fuse holder for my blower motor was melted and replaced by a previous owner, as well as the blower motor. The crimps on that install were horribly corroded.

I replaced that glass inline fuse holder with an ATC fuse holder and no more issues.

 

smart.

Also, check for bad grounds.