Anyone have the cab heater randomly work/not work?

[SIMXVertigo]

So about 2 months ago I went out to start the truck (97 M107 and the in cab heater will not turn on. I mean nothing will work. No heat and the blower won't turn on. I tested the fuses, ran a volt meter on the panel and everything is getting power. I came back a few days later and it worked just fine. Fast forward today as I go out to start the truck to bring up to the front bay so I can swap the air dryer in the morning and the heater wont work. Drive the up to the bay and the heater works! I'm at a loss. NOW, before anyone says it, I'm going to go over the TM's in the morning and see what I can find.

Anyone have ideas?

 

[coachgeo]

Will (Suprman) has mentioned that the Power Supply Panel's soders on the back side at times need some work so that might be a place your loosing voltage contact?? Ground wire??

 

[NDT]

There is a thread here that discusses an electrical connection in the heater that is faulty and can actually catch fire.

Found one thread, think there is another:

http://www.steelsoldiers.com/showth...er-Switch-Failure-amp-Repair&highlight=heater

The other:

http://www.steelsoldiers.com/showth...-caught-on-fire-this-morning&highlight=heater

 

[TNriverjet]

There is a thread here that discusses an electrical connection in the heater that is faulty and can actually catch fire.

Wow, that's good to know NDT! I hadn't picked up on that thread in all my reading to date.

 

[scottmandu]

Will (Suprman) has mentioned that the Power Supply Panel's soders on the back side at times need some work so that might be a place your loosing voltage contact?? Ground wire??

This only applies to the 2nd gen electrical system.

 

[Suprman]

The switch has the speed resistors, which are coils of wire, built on to the back of the switch. Not the best design but as long as all is in place as intended it works. Something gets bent a bit or out of place and you can get a nasty short. The coiled wire will light up like a light bulb. Take the heater face off and peek around in there. I have seen the fans go bad if the motor has a bad winding I could see it stopping on the bad one here and there and not wanting to spin up till it moved a bit to a good winding.
Will

 

[tburk49760]

I have a complete other than leaky core takeout heater should you need parts. The switch and motor are great...

 

[DiverDarrell]

Also the breaker type fuses can act a bit funny. But my best advise is a hammer and if that doesn't fix it , then it must be an electrical issue. I also have a complete takeout heater unit as well.

 

[800summit]

I had the same problem with mine, the problem was the fan switch, it melted a contact. and the wire then came off the heater switch.I was able to solder a new wire directly to the switch, then ordered a new switch as a backup.