Another no dash lights thread

[John_parkeriv]

Hey y'all,
Wrapping up my 66 and I'm working on creature comforts / safety items. Just got to the dash lights and I'm dumb founded. I'm getting 12v to the bulb socket with the headlight switch on. Twisting the knob changes the voltage so I'm thinking that works. Everyone says that grounds are the culprit in other posts, so a ran a ground wire from the battery to the socket housing and the little spider clips, nothing. Tried swapping the bulbs with the turn signal bulbs and the signal lights still work.

Another note, no wiring diagrams I can find (like SeaBiscuit68's) even show those bulbs or wires in the diagram.

Honestly kinda at a loss. What're y'all thinkin'?

TIA,
John

 

[Oldtimer]

Take a look at Seabiscuit's 72 schematics. Cluster lights are similar for all years.

 

[Brush Hog]

Are they LED bulbs? If so flip them around.

 

[John_parkeriv]

Are they LED bulbs? If so flip them around.

Not LED, may even be the original bulbs.

 

[Broncobowsher]

Are the bulbs burned out?
Clean the contacts. metal with an oxide layer won't conduct.
You have a meter, tested for 12V at the socket. Put a bulb in the socket, don't put the socket in the housing. Check for 12V on the spring terminals that will be ground. Nothing, you are having issues with the socket/bulb. You do have 12V, apply a ground to complete the circuit. Did that work? Was it a good clean ground?
Gets tricky, but do you loose the 12V to the bulb when the ground is good. This would be a weak 12V (dimmer is dimming a lot). This is an easy test at the dash light fuse. And is the fuse good with clean contacts?

And the overlooked, you do have the headlight switch turned to the left (brighter dash light setting)?

 

[Brush Hog]

I’d make sure bulbs are good. Even get new ones if you think they are original.

 

[John_parkeriv]

Turns out my wiring switch is INCREDIBLY touchy. I hooked a ground straight from battery neg and nothing happened. Wiggled the knob a little and it flickered. Managed to find the sweet spot to keep it on.

Bad light switch?

 

[Broncobowsher]

Often you can just run the switch a bunch and the contacts will wear clean. I've done that a handful of times on old trucks that have been sitting for years. floor dimmer switches that may leave you without headlights? Stomp the switch about 100 times and they work just fine now. I've pumped headlight switches the same just to get repeatable headlights. I see no reason you wouldn't have to do it for the dash lights as well. The more you wiggle, the more the contacts will rub themselves clean. Best part, it's free. The part quality of the old stuff is typically better than the new parts store stuff anyway. Unless it is really broken. The it will get worse and you can replace the switch anyway.

 

[m_m70]

The part quality of the old stuff is typically better than the new parts store stuff anyway

Yup! Truer words have not been spoken!