Electrical Problems

[penniwinkle]

I thought I had my wiring all straight but should have tested better.

I rewired my truck (1951 1/2 ton) - added new fuse panel, new light switch, new guages and new ignition switch. Initial testing showed all lights work (headlights, park lights, tail lights, signal lights, etc). The new guages all worked (Autometer- new oil guage, gas, temp, and voltmeter). It seems I did not test the headlights with the switch ON or motor running. When I turn the headlights on with the ignition swt on or motor running, all my guages appear to loose power (as if the ignition switch is turned off). I turn off the headlights and the guages power back up.

I assume that when I turn on the Headlights, the guages somehow loose power or ground. The guage power runs directly from the fuse panel and the guage lights run from the headlight switch. Only thing common between the guage power and guage lights is the grounding wires - I attached them all together with a single wire to chassis ground.

Anyone have any suggestions? The situation does not blow any fuses so am thinking the headlight switch is somehow making the guage power loose it ground.

Thanks
Roger

 

[vwnate1]

Interesting .

Did you test this by trying a jumper wire from the gauge panel to the cab ? if it's a ground problem , that'll fix it .

I assume if you've had the whole truck apart for re painting , you've added a ground strap between the cab and the engine or chassis ? (better yet , two cab ground straps , one to each) .

 

[penniwinkle]

Thanks Nate, for the suggestions. I did install a new ground strap to the body and a new one to the engine. I'm going to rework all the wiring on the guages and the headlight switch in the morning.

Roger

 

[spika]

I did a stupid one time and had some real weird things like that happening. After much troubleshooting of deeper potential issues, I discovered that I had the headlights wired wrong...the terminals are not high-ground-low like you would suspect; they're high-low-ground. If you hook them up wrong, the'll be trying to ground through other components and everything goes goofy.

Just in case it's something this easy...

 

[penniwinkle]

Well, I spent several hours on this today. I went thru the wiring in the dash several times and all ok. When I initially installed the guages, I grounded all the guage wires to a single bolt under the dash. This ground worked ok until I turned on the guage lights. After doing several tests on this, I came to the conclusion that it was a 'half-ass' ground. I moved the ground from the dash to a bolt in the steering column brace and everything worked as it should. A bad ground or one that does not make a great metal connection will cause a lot of confusion. I felt like the ghosts of my Dad and Grandad were laughing at me all day.

Roger

 

[spika]

Great to hear you got it solved!