Instrument cluster oddities

[Bumpside Collector]

I have a 72 F-350 that I recently bought. I have a problem with the instrument cluster and heater control lights. They will dim and flicker and occasionally go out. The head lights will also dim. The turn signal indicator lamps in the cluster work fine and the dimmer switch works fine also. Sometimes when I hit a bump the lights function normally. I think I have a loose connection somewhere but I'm not sure. What do you guys think?

[knightfire83]

Sounds like a bad headlight switch. The dash / heater lights run off a rheostat on the front of that switch. Could be worn out.

[Bumpside Collector]

Thanks. I thought it might be the problem but I wasn't sure. I'll look into it some more and see what I can find.

[Thunderfoot]

Also check the ground wire from the back of the engine to the cab and make sure it is make good contact.

[Bumpside Collector]

Also check the ground wire from the back of the engine to the cab and make sure it is make good contact.

Thanks, that wire never occurred to me. I pulled the switch and it looks to be relatively new. I know it isn't original. I haven't seen any broken wires so I guess I'll just look it over real good one more time and then put it all back together and see what happens.

[Bumpside Collector]

Well I got it all back together and then had some other problems. While solving those problems I think I found the cause of this one. under the battery tray the wires had been rubbed bare and they were shorting together. I think I got it fixed now.