Bad Ground?

[ken]

So I drove the 1028 into town to get some Diesel and on the way home the heater stopped blowing. The Gen 1 light didn't come on and my VDO gauge still read 28.5 volts. 5 miles later when at a stop sign the turn signals wouldn't work eather. I got home and checked the heater fuse. It looked and ohm'ed ok. I put my multi meter on the fuse terminals and got 14.7 volts on both sides. That can't be right. I jumpered the fan motor from the battery and it worked good. When starting the truck the Gen lights come on like normal. With the truck running while I was under the dash the heater started blowing again. Does this sound like a bad ground to ya'll?

 

[Rustyshackelford]

Clean all grounds and connections after disconnecting the batteries. I'd give you 50/50 odds that would fix it.

 

[ken]

Thanks Rusty. That's what I'm thinking too. I'm thinking of adding some extra grounds between the body and the engine also.

 

[MarcusOReallyus]

I'm thinking of adding some extra grounds between the body and the engine also.

No need. Just clean what you have. If you need more grounds, it's between body parts, not between body an engine.

I put my multi meter on the fuse terminals and got 14.7 volts on both sides. That can't be right.

That's exactly correct. It should be the same if the fuse is intact.

 

[ken]

Marcus, That was with the fuse removed. To have voltage on both terminals that the fuse plugs into threw me.

 

[cpf240]

Marcus, That was with the fuse removed. To have voltage on both terminals that the fuse plugs into threw me.

Two things... GEN 1 shares the heater blower circuit. That may account for the strange readings. Secondly, the blower motor speed switch is known to have issues with poor connections, sometimes resulting in melted parts and magic smoke. I'd suggest pulling the speed fan speed switch and checking it out.

 

[dependable]

One other thing to check is the resistor for the blower motor, if it is rusted or shorted, it can cause strange symptoms on that circuit. That is in firewall behind the rear battery, just follow the wire from blower. If you have had mice in the blower motor housing, this problem is common.