Interesting Heater Wiring Issue

[glcaines]

I fired up the Deuce today for an exercise run of ~20 miles or so. I decided to check the oil after shutting down. I was outside the cab and reached inside and cut off the accessory switch and cut the fuel to stop the engine. I heard a very loud rumbling sound coming fromt he engine compartment. It turns out it was the heater motor running. I looked back inside the cab because I thought I must have left the accessory switch turned on. I hadn't. The heater switch was in the HI position. I turned the heater switch off and the blower motor stopped turning. The heater motor has never worked before. Apparently, it is wired incorrectly and the accessory switch doesn't cut it off. Something to check out tomorrow.

One thing is certain, the blower motor will need replacing - it was really screaming and rattling, although I guess it could be the squirrel cage scraping on something.

 

[tm america]

no thats just how they are wired the lights can also be turned on without the main switch being on .i installed a keyed switch in the number 10 wire that feed the power to everthing in the truck .with the key off nothing works lights, heater ,starter , nothing

 

[glcaines]

I looked at the wiring diagram and you are right. I just assumed that the heater was wired through the accessory switch. I have been lucky that the heater motor hasn't turned itself on before, because I haven't paid any attention what the heater switch position was. I'm going to take the thing apart tomorrow and determine what the source of the noise is.