Wiring help needed from the gurus (1 Viewer)

[TomB12]

Hey all, was hoping for some input on getting my headlights to work again so I don’t have to make my head explode tracking down the issues m. Here’s the background….the FJ40 I bought had a plow and lights. The previous owned had this toggle switch (see picture) wired to the lights. When it was flipped it turned the regular headlights off. I don’t want the plow so I removed everything including the toggle switch.
After removing the switch I reconnected the red/green and red/yellow wires from each headlight. He had spliced into them from inside the engine compartment. After reconnecting them the headlights don’t work. The running lights all work fine. I am sure there’s more that needs to be changed back but am not sure what. Any input would be awesome!
On another note if anyone is interested in the plow set please drop me a note.

 

[rkymtnflyfisher]

Sounds like you are going to need to dig into that harness to find out what's wrong.

Do you have proper wiring diagram?

 

[dmaddox]

Hello and welcome @TomB12 I'm guessing you are working with a late 70's FJ40 with a V8 conversion based on what I am seeing. Could you let us know what exact model and modifications you have?

If you reconnected the wiring at the headlights in the engine bay - what is the situation inside the cabin at splice location of the toggle switch?

 

[TomB12]

Hello and welcome @TomB12 I'm guessing you are working with a late 70's FJ40 with a V8 conversion based on what I am seeing. Could you let us know what exact model and modifications you have?

If you reconnected the wiring at the headlights in the engine bay - what is the situation inside the cabin at splice location of the toggle switch?

Thanks and my apologies for not including that information. You are correct, it's a 327 Chevy Conversion (1967) and the FJ40 is a 1974.
Today I decided to put the toggle switch back in so I’ll have headlights for now and then I can better reverse engineer it.
There are 6 wires going into the toggle switch. 2 are red/green and 2 are red/yellow, all from the headlights (they show as red in black in the picture because they are spliced). The other 2 go to the plow lights, which I want to remove. When you flip the toggle switch one way the plow lights go on and when you flip it the other way the regular headlights go on.
I want to remove the plow lights and toggle switch. So the question really becomes how do I wire/rewire it without the switch?

 

[TomB12]

Sounds like you are going to need to dig into that harness to find out what's wrong.

Do you have proper wiring diagram?

I do have a good wiring diagram, just need to sort it all out!

 

[dmaddox]

Which color are going to your plow lights? Just disconnect those if you are removing. Then, just connect your headlight together so the switch isn't interrupting them. On the back of the plow lights, what colors are going ot the lights?

 

[TomB12]

Which color are going to your plow lights? Just disconnect those if you are removing. Then, just connect your headlight together so the switch isn't interrupting them. On the back of the plow lights, what colors are going ot the lights?

The black and white wirer go to the plow lights. So if I remove the switch where do the red/yellow and red/green wires go?
Yesterday I took out the switch and reconnected the red/yellow and red/green wires where they had been cut and spliced to the toggle switch. When I reconnected them the headlights didn’t work.

 

[projectTuRD]

Does a 74 have the wiring junction blocks on the fenders up front?
I’d start at the plow and remove all the wiring all the way to the switch, relays, battery, etc.
Then go to that toggle switch and do like you did.
Then go to the junction blocks and reinstall the headlight wires per the diagram.
Mine is messy, and missing the original connectors, but I just replaced the blocks and confirmed everything works as it should on mine (02/69).
The headlights on mine run through the ‘stomp switch’ on the floor board. I had to replace it to get mine to work correctly a couple years ago.

 

[kerplunk]

The Haynes version of the 74 wiring diagram shows RY (Red Yellow), RG (Red Green) and WB (White Black) going to the headlight. But I always get a little lost trying to follow lines on those things, and it almost looks to me like the goes to the wiper switch in the copy I got?

You can verify what on the headlights looking at the wiring off the back of the headlight plug.

And if those match 4 of the wires on the back of that thing, my first try would be to just see if hooking those straight up back together (i.e. RY to RY, etc.) works?

 

[Engineer8000]

I have a 10 72, there is a red wire from the fuse block headlight fuse to the headlight switch, is that connected?

 

[TomB12]

Does a 74 have the wiring junction blocks on the fenders up front?
I’d start at the plow and remove all the wiring all the way to the switch, relays, battery, etc.
Then go to that toggle switch and do like you did.
Then go to the junction blocks and reinstall the headlight wires per the diagram.
Mine is messy, and missing the original connectors, but I just replaced the blocks and confirmed everything works as it should on mine (02/69).
The headlights on mine run through the ‘stomp switch’ on the floor board. I had to replace it to get mine to work correctly a couple years ago.

View attachment 3413837

Does a 74 have the wiring junction blocks on the fenders up front?
I’d start at the plow and remove all the wiring all the way to the switch, relays, battery, etc.
Then go to that toggle switch and do like you did.
Then go to the junction blocks and reinstall the headlight wires per the diagram.
Mine is messy, and missing the original connectors, but I just replaced the blocks and confirmed everything works as it should on mine (02/69).
The headlights on mine run through the ‘stomp switch’ on the floor board. I had to replace it to get mine to work correctly a couple years ago.

View attachment 3413837

Thanks for the info. Mine does not have the fender junction boxes. What year is yours? From what I saw in the wiring diagrams it seems they started wiring the the headlights through the high beam floor switch in 1975. At least that’s what I saw.

 

[TomB12]

I have a 10 72, there is a red wire from the fuse block headlight fuse to the headlight switch, is that connected?

Thanks, I think I saw that it was but will need to double check.

 

[rkymtnflyfisher]

WB-ground
RG-Red with green tracer goes to the headlights via the light switch on the dash
RY-Red with yellow tracer, same as above.

Delete all the wires that aren't OEM, the reverse engineer it from there.


Do you have a good multi meter?

Does the OEM switch still function in any capacity or has it been bypassed?

 

[rkymtnflyfisher]

I have a Jul 1974, and I'm currently working on the rear half of the wiring harness.

The wiring diagram floats back and forth across my garage, truck, desk, kitchen table, toilet, you name it, I've been staring at it for a bit.

 

[TomB12]

The Haynes version of the 74 wiring diagram shows RY (Red Yellow), RG (Red Green) and WB (White Black) going to the headlight. But I always get a little lost trying to follow lines on those things, and it almost looks to me like the goes to the wiper switch in the copy I got?

You can verify what on the headlights looking at the wiring off the back of the headlight plug.

And if those match 4 of the wires on the back of that thing, my first try would be to just see if hooking those straight up back together (i.e. RY to RY, etc.) works?

Thanks, yes that’s what I saw on the wiring diagram as well. The w/b seems to go to the wiper switch. The w/b I was referring to earlier is different though. The previous owner just happened to use w/b to go from the plow lights to the toggle switch. I will have to confirm that the w/b from the headlights goes to the wiper switch as it’s supposed to. It’s odd that it would but then again I’m not a wiring expert. Perhaps it’s just to complete the grounding circuit?

 

[rkymtnflyfisher]

Thanks, yes that’s what I saw on the wiring diagram as well. The w/b seems to go to the wiper switch. The w/b I was referring to earlier is different though. The previous owner just happened to use w/b to go from the plow lights to the toggle switch. I will have to confirm that the w/b from the headlights goes to the wiper switch as it’s supposed to. It’s odd that it would but then again I’m not a wiring expert. Perhaps it’s just to complete the grounding circuit?

Most of the time it is best to remove all PO "extra" wires.

 

[TomB12]

WB-ground
RG-Red with green tracer goes to the headlights via the light switch on the dash
RY-Red with yellow tracer, same as above.

Delete all the wires that aren't OEM, the reverse engineer it from there.


Do you have a good multi meter?

Does the OEM switch still function in any capacity or has it been bypassed?

I do have a decent meter. Yes the headlight switch does still function because it has to be on for the lights to work, even with the toggle switch.

 

[rkymtnflyfisher]

I do have a decent meter. Yes the headlight switch does still function because it has to be on for the lights to work, even with the toggle switch.

Should make it a little easier to figure this out then. At this point it should almost be a color to color splice, eliminating that aftermarket toggle.

Looks to me that you need to delete all the conductors going to the plow lights, then just reconnect the conductors that 1-feed the toggle, 2 that are going to the headlights. It should (aside from any extra conductors added to extend to the toggle location) a color to color splice.


I bet if you follow the conductors back from that toggle switch you're going to find a hack in the main harness under the dash.

 

[TomB12]

Should make it a little easier to figure this out then. At this point it should almost be a color to color splice, eliminating that aftermarket toggle.

Looks to me that you need to delete all the conductors going to the plow lights, then just reconnect the conductors that 1-feed the toggle, 2 that are going to the headlights. It should (aside from any extra conductors added to extend to the toggle location) a color to color splice.


I bet if you follow the conductors back from that toggle switch you're going to find a hack in the main harness under the dash.

Yeah, you are probably right about the hack. I obviously knew what he was doing to do what he dig but it’s a bitch trying to follow it.

 

[projectTuRD]

Thanks for the info. Mine does not have the fender junction boxes. What year is yours? From what I saw in the wiring diagrams it seems they started wiring the the headlights through the high beam floor switch in 1975. At least that’s what I saw.

Mine is an 02/69. After the dash switch, it is routed through the floor switch en route to the front.
My mistake earlier, I thought for some reason it went to the floor switch first