Headlight Switch Constant Power Wire?

[focusedontheprize]

Hi everyone,

The previous owner did some splicing and some "creative" wiring on my 1986 Chevrolet C30. I am in the processing of adding the LMC quad headlight harness upgrade when I realized I do not have headlights, parking lights, clearance lights, fender lights, or tail lights. I am not that electrical inclined so please excuse me if I do not use the right terminology.

What I have done:

- Check at battery I have 12 volts
- Traced positive cable to starter and checked fuseable link (visually) and do not see any indication of exposed wires or of it being damaged
- Confirmed at junction block on firewall I have 12 volts which has 3 red wires running to it (2 fuseable links)
- Confirmed at headlight relay on inner driver's fender I have 12 volts
- Confirmed the fuseable link from the junction block to the back of the main fuse block I have 12 volts
- Confirmed I am not getting any volts at the headlight switch red wire
- Confirmed if I bring direct power to that red wire on the headlight switch the headlights will work.

So my next step is chasing that red wire from the headlight switch back to see if there is a break somewhere.

Questions I have:
- I believe that red wire from the headlight switch goes back somewhere in the fuse block, is that correct?
- If so, where does it go? All the labels on my fuse block have faded off.
- Should I be able to turn the headlights on without having to have the key in the ignition? I believe I had read that red wire to the headlight switch should be a constant 12v from the battery.

Thank you for all the help, as I mentioned I am not that great at electrical and am trying to cover all my bases from what I have read about online.

[hatzie]

Download the 1986 wiring diagrams.

There are typically two RED power wires at the fuse panel. One of them feeds the headlight switch.

[focusedontheprize]

Originally Posted by hatzie

Download the 1986 wiring diagrams.

There are typically two RED power wires at the fuse panel. One of them feeds the headlight switch.

Thanks hatzie. Just to be clear are there 2 red wires that run from the junction box into the fuse panel?

[hatzie]

Originally Posted by focusedontheprize

Thanks hatzie. Just to be clear are there 2 red wires that run from the junction box into the fuse panel?

GM changed the fusible links at the starter and J-studs nearly every model year. You need the GM wiring diagrams for your year to figure out the proper locations and functions of the fusible links and the routing of the power distribution wires inside the cab.
There are usually two Circuit 2 main power connections through the bulkhead block no matter what year. One on an outside edge and one buried in the middle.
In 1986 both Red Circuit 2 main power cables to the bulkhead plug go from the J-Studs on the firewall to the bulkhead plug. Other years ran one or both down to the starter BAT stud. There were yearly power distribution changes inside the cab as well.

In 1986 the Circuit 2 power wire on the outside edge of the bulkhead connector has two wires exiting from one terminal in the bulkhead plug inside the cab... One of those wires is direct to the headlight switch. The other one goes to the three fuses on the lower LH corner of the fuse panel.

[Wgesnerjr]

Just in case it will help, here is a pic of my 85 fuse box with the labels for each fuse.

[focusedontheprize]

Thanks Wgesnerjr for that photo. I saved it and it was a huge help.

Thanks hatzie for the information. Today (just returned from vacation with the wife) I chased down the red Circuit 2 wire from the headlight switch connector to the back of the fuse panel and located it (2nd slot from the bottom on the left hand side of the fuse panel). There is continuity so I had the right terminal however there is no power at that terminal. When I ran a jumper wire to it - the headlights worked.

After reading the schematics I thought I would look at the ignition switch to see if that is the culprit as the red Circuit 2 wire terminates there as you mentioned.