help me identify this headlight switch

[pistachioted]

I want to identify this switch and learn what gets connected to each terminal.
I've seen the knob on Chevy trucks before but don't remember what year this is from. Would appreciate help!

[mr48chev]

Looks like a later model GM switch.

You can probably figure it out in a couple of minutes with a ohm meter or continuity tester.

This might do it.

[joedoh]

its a ford foxbody (mustang, small LTD/futura) headlight switch. the tapered ring is the giveaway.


https://www.ebay.com/itm/79-86-Ford-...L/123072256437

if you use it, be careful using the dome light function, GM stuff is ground triggered and ford (of that era) was 12v+ triggered.

[pistachioted]

Thanks Mr. 48. As you see in the photo, the red wire is from the battery and in the position of the diagram you sent. None of the other tabs read 12v with the switch off. When I pull the switch to the first detent OR all the way out, both tabs in the opposite corner read 12v. All the others stay at zero.

There are letters near some of the tabs but not all of them. You can see D2 in the photo and D1 next to it. The red wire is labeled A and the one next to it is B. There is a P and an R but you can't tell for sure what tab they are for and two other tabs are unmarked.

MAYBE I am smart enough to figure it out with the ohm meter, but I was hoping someone would recognize the knob and tell me what year it is so I could find the proper wiring. The diagram you sent is close but not the same.

[pistachioted]

Ford! Okay, that's a start. Any idea which tabs go where?

[joedoh]

well you have probably googled "ford mustang headlight switch wiring" by now, but if you havent, I did.

[pistachioted]

Thanks again, Joe. Yes, I found that online also. My switch seems to be the same as this except that I do not have the tab labeled 'P' even though the letter is there. I need to get out the ohm meter though to figure out where every thing goes. I think the battery wire goes on 'A'....Ted

[joedoh]

if you look at the diagram, A and B are connected through a circuit breaker, with one important difference, A is AFTER the circuit breaker so you will be bypassing the protection of it if you use A for the batt instead of B

not having a P would just mean that your switch doesnt have separate front and rear park light outputs, some early cars likely did. front and rear park lights get attached to the R connection at that point. I used to be a car stereo installer (part of why I recognized the switch) and remember a few cars had separate park light systems, although mostly it was german/european cars with separate left and right park light circuits.

[pistachioted]

The switch is for my '46 Chevy pickup so no breakers. I have one fuse for the whole system and thought to add another one just for the lights, sound good? I presume the breaker in the diagram is external and not built into the switch.

Good to learn about what 'P' is for.

[joedoh]

Originally Posted by pistachioted

The switch is for my '46 Chevy pickup so no breakers. I have one fuse for the whole system and thought to add another one just for the lights, sound good? I presume the breaker in the diagram is external and not built into the switch.

Good to learn about what 'P' is for.

no, the cb is internal to the switch, if it wasnt there would be another pair of terminals to take out and put the power back in before it goes out of A. Its there so if the headlights/ brake lights draw too much current the CB trips (self reset) instead of blowing a fuse (manual reset).

[_Ogre]

vehicles don't fuse the headlights, cuz if the fuse blows you loose headlights. dark period
straight from the battery to B, if you have an overload condition the breaker will trip/reset/trip/reset
your headlights will flash, allowing you to safely pull over
there should be a baf (big a$$ fuse) or fusible link at the battery to protect the wire harness, if it goes you had a fire condition

tf trucks from the factory had no fuses other than the dash light fuse on the switch, unless you added an option
there are 2 breakers built into the switch: headlights and all other lights
brake lights, turn signals, heater and electric wipers were all optional on old trucks and should be fused

[pistachioted]

Okay, so power from the battery should go to B. But with 12v on B, none of the other tabs get power at all. I suppose that means the cb is broken, permanently open. The only other explanation is that the circuit diagram is the wrong one for my switch and that doesn't seem likely.

[pistachioted]

Maybe the diagram isn't right for my switch after all. With battery on A, pulling out the switch gives power to R and to the tab in the 'I' position (except that tab doesn't have an 'I' label on my switch). There is no 'H' label on my switch either and the tab in the center does NOT get power when the knob is pulled out.

[joedoh]

Originally Posted by pistachioted

Maybe the diagram isn't right for my switch after all. With battery on A, pulling out the switch gives power to R and to the tab in the 'I' position (except that tab doesn't have an 'I' label on my switch). There is no 'H' label on my switch either and the tab in the center does NOT get power when the knob is pulled out.

are you pulling it out two clicks? first click is parking lights, second click is headlight

[pistachioted]

Yes. I get the same result whether it is one click or two.

[_Ogre]

imo you have the wrong diagram
the orange wire has 2 terminals, i believe the orange wire should be the batt

[joedoh]

Originally Posted by _Ogre

imo you have the wrong diagram
the orange wire has 2 terminals, i believe the orange wire should be the batt

not that I mind civil disagreement

but if anyone had bothered to click the link I gave you will see 1) it is indeed a foxbody ford switch. and 2) the picture in that ad shows pretty clearly that there are not two terminals connected to the same trace.



looks pretty similar, eh? forum resize may make it too small to see the traces so click the link, its in 1600x2000 on the auction page.

the wiring on ford headlight switches did not change for YEARS, except the separate parking light terminals. later model mustangs (up to 2004!) still used the pull switch and the exact same plug and wiring. broncos, ford trucks, crown vics, everything used that switch and wiring.


if you are not getting a reading with that diagram, and you have the input on B like it should be, then either 1) the switch is bad or 2) the brass contacts have corroded. if its 1, find another switch. if its 2, channel your pubescent youth and pull the switch in and out vigorously for a while. the brass contacts sometimes get corrosion from just sitting and cycling them cleans it.

[pistachioted]

Ogre, I don't know what made you think this, but you were right. The batt feed goes where my orange wire is on the first photo.
Joedoh I think it is a Mustang switch like you said.
But I have one batt wire to the center and one to the top left that keeps the turn signals and brake lights on even when the lights are off.
I have one extra wire and can't find what it goes to yet. Maybe for the dash light???
But thanks for the help from both of you!!!