Hot fan switch

[Vette66AirCoupe]

With the weather making the evening return from the dwindling car shows a bit on the chilly side it's time to crank the heat up. Last weekend when I got home from a show I noticed that the fan switch knob on my '66 was very warm. Since I know little more than the fact that resistance creates heat I'm at a loss for understanding the problem. It's not so hot that you can't hold onto it but it is definitely on the hot side of warm. The fan seems to be operating OK. Any thoughts? :confused

 

[Geek's 65]

Try pulling fuze #2 which should isolate your heater/exhast fan circuit. Wait a bit and see if the knob chills out. If it does and then gets warm when you replace the fuse, then you are probably right. You have some resistance somewhere that is providing a current path. That circuit feeds both the heater switch and the luggage compartment exhast fan. I would pull the plug on the exhast fan switch to see which of the two is supplying the resistance. With the exhast switch pulled out, if the heater knob remains hot I would look there. If it cools down again, the culprit lies in the exhast fan circuit. My guess is one of the switches has broken down and is allowing a small amount of current to the respective fan motor through the speed control resistor at such a low level that the motor doesn't actually turn.