No Marker Lights or Dash Lights

[72_EB]

Maybe folks can help me make quick work of this fix tomorrow. I'm making progress on my '76. On the electrical...

What I have good-
Brake lights
Headlights Hi/Low
Turn Signals (Front and Back)
Hazards (Front and Back)


What I don't have-
Front or Rear Markers (front work, but they flicker, headlight switch makes crackling noises and I shut them down quick)
No instrument lights (Could be a bunch of dead bulbs...yes...i've tried turning the dial )


I'm betting on grounds on the markers and checking that first tomorrow. Any think else jump out at anyone?
Anyone else running better grounds right off the assemblies? Aren't the front signals/markers grounded off the core/grille support?

 

[DirtDonk]

Well, the crackling from the switch to me is a dead giveaway that you need a new switch.
I suppose that with some bad grounds your switch might just be flipping out, but I doubt it. They're pretty robust, but when they're old they give up. Both of those circuits are through the switch of course, so those two clues say "switch" to me.
Frankly, if it's old anyway, it's cheap insurance to change it out now anyway while you're fiddling around under the dash. It doesn't rule out the bad-bulbs-in-the-dash scenario that you mentioned, but it sure sounds like a swich.

First things first though. Like you said, check and repair all the grounds at the markers, check the sockets, check for dash grounds and all. And then go for the rest. But a good check of the circuits to make sure that you've got 12 volts to the lights could also tell you if the switch is involved in the mystery.
Having been there, my money's on the switch for at least part of this.

Paul

 

[DirtDonk]

Oh, and I think my grounds on my '71 are on the support for the front markers, but the inner fender for the side markers. Been awhile, and it's dark out, but if you need me to I can double check in the morning. They're pretty obvious though if I remember.

Paul

 

[scarbrough351]

on your head light switch is a spring that turns dimming or brightening your instrument panel lights. i had the same problem. the spring broke 2 days after i bought my bronco. you need to pull the headlight switch out. ( you have to push the button on the top of the headlight switch under the dash to get the knob out. i just cut the spring totally off and soildered a wire on the switch so my instrument panel would stay bright all of the time, there is no reason to dimm it.

the bulbs are probably good in your instrument lights. ( i had the same problem & if you see sparks or here a grinding noise the you need to cut the old spring, no reason to buy a new switch)

and the side maker lights are the same bulbs as licence plate bulbs, there are probably corroded, just replace them.

 

[72_EB]

Getting close...
Still got something messing up my markers and dash lights.
If I pull the headlight switch out to markers, in about 2 secs its starts crackling and I shut it down. They come on for that brief time though. I think I have to have something grounding them out. Right? ?:?

 

[DirtDonk]

I don't think so. Not necessarily anyway. The lights are grounded on one side already of course, but if you're getting a short, then it sounds like you're getting a short in all of them at the same time, and that's very unlikely
Your switch has it's own built-in circuit breaker, so if you had a real short it would cut out until you turned the switch off or the short went away.
Your crackling sound could be your breaker doing it's thing and sort of buzzing, or your "short" could be in the switch itself.

I'm not really sure how to test that other than to visually inspect it.

You've got a fuse in the panel for the dash lights so if it was in there you'd probably blow the fuse instead of having a crackling switch. All the others are protected by the CB in the switch though I think. You might as well check the fuse just to see if it's blown, but if it is, then you wouldn't be getting the crackling sound if it was a bad dash light circuit.
I know it's a pain to remove the switch, but it's not all that bad once you stand on your head with the t-case shifter in your armpit and turn your arm into a pretzel. Try removing the switch and inspecting it at least.
It sounds like you've already checked the other things. And your common-denominator is the switch.

Paul

 

[72_EB]

Thanks for the help, Paul. Couple new questions for ya.
http://www.bronco.com/graphics/diagrams/75_77wd7.gif
I'm going to pull the rectangular dash lights out today and just complete the circuit with wires. This above diagrams looks like they move through them. Maybe they are both burnt out and that's my problem.

My headlight switch is brand new, but maybe it is bad and got returned and sold to me? Headlight foot dimmer and headlight switch do not have to be grounded to the floor or dash? Doesn't look like it in this diagram. I've been testing out of the dash, since like you said, it's a pain to pretzal under the dash like that for too long.
http://www.bronco.com/graphics/diagrams/75_77wd4.gif

But I think I will try the completing the dash lights circuits and if that doesn't work, I will pull the switch out of my '72 which I know everything works perfect and see what happens. Thanks again. Happy holiday weekend!

 

[Naildriver111]

Make sure your dimmer switch is plugged in and screwed to the floor. Then try unpluging 1 light at a time and turning on the switch afterwards. And don't forget the tag light,