I just put in a new blower motor resistor and before putting back into the housing i decided to test to make sure it work and I got all fan speeds now but noticed the resistor got very hot in just a three or four seconds. I shut the car off after a few seconds as I didn't want to destory this resistor. Do they normal get very hot?

I still need to check for a water leak as the old resistor did fail after drving four hours in the rain, but I didn't see any signs of water, carpet dry, air filter dry and no signs of water staining.

 

This would be normal.

 

Don't know for sure about the specifics, but resistors are designed to get at least warm, if not hot. If it gets hot to failure, then you got other problems, like a short somewhere including in the motor. But, you knew that already.

 

I let it run ten minutes and it seems ok. Hit it with my IR thermometer and it gets to 117 F in a matter of seconds and then sits there. That's on speed 1. On speed 3 it drops to 105 F and on 4 it drops down to 90 F wich is about the outside air temp.

 

Many blower motor resistors are designed such that they would burn up if they are not in the path of the air from the blower fan. They are that close to tolerance. Not because manufacturers like to burn stuff up but higher wattage resistors get very big and very expensive..... even those will get hot. That's how a resistor works, turning current into heat.

As ChevyMgr said, this would be normal.

 

I I pulled the cowl today and found the previous owner (over 3 years ago) had replaced the rubber seal with duct tape. I can't believe it hasn't leaked before this.

Went to the dealer and bought a new water deflector.