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My heater has decided to stop working. What is the best way to figure out what part is not working? There is the element behind the switch and then there is the fan. Call me stupid but I don't know anything about electrical. How should I narrow my scope of diagnosis? Thanks.

Check to make sure that all of your connections are good. A bad ground will make things not work.

Also check the hot side with a VOM to verify voltage to the fan motor and resistence at the swtich.

If everything checks out good but the heater still doesn't work, then I'd probably replace the fan.

As red58 says "electricity makes my head hurt".

OldBlue58,

I am not real familiar with the Task Force truck so I might be in left field. To do any electrical troubleshooting justice, the least you should have is a voltage tester. This is a ice pick looking affair with a wire and alligator clip coming out of the handle and a small light inside. When you attach the alligator clip to a good ground, and stab a wire or connector with the sharp end, the light will illuminate if power is present.


Your search should include these thoughts..is the heater switch getting power to it (fuse), is the heater switch getting power through it , and is the heater motor getting power to it from the switch.

If all these are "yes", then it is probably the motor that is defunct. I don't know if you have a actual fan, or a squirrel cage, but maybe the motor is turning, and the fan is laying in the bottom of the heater housing.

These are some ideas that will narrow the search, even for a electrically challenged Stovebolter..good luck.

Stuart

Thanks atomarc & Brendan M, the switch fell out today and dangled, hit the dashboard side and sparked. I had to yank it off the dash. Hopefully I didn't fry anything. My father kept mentioning the fan bottoming out which is kinda what you mentioned so I will also look at that. I recall my father working with it and the element behind the switch was orange-hot. It doesn't do that now. I'll ask my neighbour if he has a voltage meter and that should narrow it down. Thanks for steering me right. :-)

blue - that coil on the switch is supposed to get hot when the switch is set to less then full speed - that's it's job, to reduce the juice to the fan motor - not getting hot may be due to it being burnt out, or it may be due to the motor no longer drawing any current

you can run a jumper temporarily from the hot side [input] of the switch to the motor lead, if the motor runs the problem is the switch, if it doesn't, the problem is the motor

Bill

Bill, thank you very much. I will give that a try. I'd rather know the fan works or not before getting in there. It didn't seem to get red-hot lately so it might be gone. It doesn't look worn at all. Thanks again.

I've been testing the electrical with a friends gizmo which is 2 wires with a little light in the middle and I am finding that the light works from both ends of the heater switch when touching the dash. I then went to take a closer look at the heater. I was able to remove the vent housing but am baffled by the fan housing. Do I approach it from the glovebox side? I don't see the fan moving when the switch is on but it looks to be inplace. Anyone know how to get this apart?

jumper batt voltage to theblower motor this will bypass all ele if blower works then look at sw..did you check fuse??? doc

I just took the glove box out, looked at the connector from the heater switch to the blower and it is "live". I am attempting to figure out how to remove just the blower motor but it seems to be connected to the frame at the firewall in 1 piece. It seems I have power right up to the blower. Maybe the blower is "blown".

Well, I just figured it out. I played with the connectors a bit with the little light thing and realized the connection wasn't being made. I cleaned up both ends and the blower worked.

I just wanna say a Big Thank You for the help. One more thing learned.