Headlight Switch help

[jrbCO]

So I’m working on a “new to me” ‘76 Bronco and installing a Dakota Digital speedometer. I have the dash off and checking all connections before I tidy up the wiring and reinstall the dash. The Bronco has a centech harness and everything electrical worked before I deconstructed it. My issue is that I cannot get the headlights to work now. I honestly did not rewire anything around the headlight switch, but did have to rewire turn signals and a few other things behind the speedometer. Everything else works now: turn signals, hazards, brake lights. I have 12v power coming into the HLS feed and Park feed at the headlight switch. I feel like I must have a disconnected ground, but not sure where. Any ideas or thoughts to check the switch itself?

 

[ba123]

Check for power at the headlight bulb. Ground I think is at the headlights.

After that, I'd check for continuity through your headlight switch...are the parking lights working?

Which headlight switch?

 

[jrbCO]

So no power at headlight with switch on. Parking lights also not on. I can’t post a picture, but it looks like the standard headlight switch sold by the usual vendors. I can get the headlights and parking lights on when I direct wire the incoming hot HLS or Park feeds to internal switch wires going to the headlights and parking lights separately. I assume that means a bad switch?

 

[ba123]

It's worth paying the tiny fee to be a member and post pics. I wouldn't buy a new switch on a hunch if neither the parking nor the headlights work...I'd bet something else is wrong.

 

[jrbCO]

Did not realize that’s all it took to post photos, thanks. I tend to agree it should be something else, but wouldn’t the fact I can get the lights on by direct connections within the switch suggest a bad switch? If I bridge the white connection directly, lights on.

 

[ba123]

No, most likely wiring is wrong. Do you know where on the SWITCH you are supposed to have power for sure? Power in the wrong place wont make it work (I know you know that).

Is it a centech switch and centech hardness for the headlight?

Just came across this thread which has some info.

https://classicbroncos.com/forums/threads/centech-headlight-switch.283848/

 

[serial car restorer]

Do the park and tail lights work? If so, check the dimmer switch.

 

[jrbCO]

Here is my switch. I see subtle difference with a “stock” switch. No headlights or parking lights with switch on. Both work if I jump a wire internally within the switch. I honestly don’t think the dimmer switch works but never really checked it before heading down this Dakota install. It does nothing currently when I have the headlights on with jump wire

 

[jrbCO]

I’ll add that besides the turn signals, the only thing related to the headlights that required a wiring change was the hi beam indicator that went to the old speedometer. I’m not sure if wiring that into the Dakota control box could contribute to my issues. Not sure where to go next with troubleshooting

 

[ba123]

That is not the same switch and not made for a Bronco so the wiring will be different.

I answered that too quickly...lemme find more info.

 

[ba123]

Yes, that is a 1979 Ford Mustang switch, like that other thread says Centech gives you.

 

[ba123]

This page will give you the necessary correct connection locations
https://tomsoffroad.com/products/66...210jSldTmpcY_vr_l_DkGA8OojbJzYzgM2XTmyB_6l4-r

assuming you got that switch from Centech.

 

[jrbCO]

Thanks. Again, this Bronco is new to me. So there is no dome light. I did exclude the gauge lights with the Dakota install, but not sure how that would cause issues. Guess I’ll try a new switch and go from there.

 

[ba123]

Yeah, looking at this other one, I don't really see how they are so different but it does say they are not interchangeable.
https://tomsoffroad.com/products/66-77-ford-bronco-headlight-switch

Is your headlight connector part of the centech or stock or you don't know?

 

[jrbCO]

Is your headlight connector part of the centech or stock or you don't know?
[/QUOTE]
Not sure.

 

[ba123]

Then I would check, with the headlight switch out, which pins have continuity between them with the headlight on and park positions. If there is none, then it’s for sure the switch. If there is continuity and the wrong pins then you know the problem.

 

[Oldtimer]

A is 12v out to Aux to brake light switch
B is 12v source from Battery
P is 12v to front Parking lights
R is 12v to rear Running lights
1 is 12v to instrument lights, dims to zero with turn of knob
4 is 12v to headlight Lo/Hi beam switch
D1 is 12v from fuse panel
D2 is 12v to Dome light

 

[ba123]

I knew someone would post a good schematic but he doesn't have that switch.

I see your edit up top showing the wring and that looks correct for the switch, so yeah, maybe it's just bad.

 

[jrbCO]

For follow-up:

Replaced headlight switch with new ‘79 mustang switch for centech harness, everything works. Odd that switch worked fine before my re-wire for the Dakota digital dash, but died after the re-wire. Glad it was nothing more complex.

 

[DirtDonk]

I don’t think anything is odd, anymore.
At least not when it comes to modern auto parts failing at strange coincidental moments.