Can anyone tell me what each of the terminals are for on the headlight switch? I know which ones are for the power, park/tail light and headlight. I always thought the tail lights came on when the front park lights came on. I hope that is right. The instrument/dimmer terminals I'm not worried about for now. What are the other two for that are on the opposite side of the park/tail and head light terminals and the third one which is in between those two. They aren't "hot' at any position of the headlight switch. Either at the park light position or the headlight position. Is the switch faulty? It's fairly new and the tail lights worked fairly recently. At the park light position on the switch I have front park lights. If I hook up the tail light wires to this terminal they work but are as bright as the brakes lights and you can't tell the difference when I press the brake pedal. I have brake lights when this wire is disconnected. I've researched the old posts and gained a little but I'm still at a loss.
This is for 60-63 GMC but probably the same for Chevy. See what you think. Have you messed with the turn signal wiring and other wiring? What all are you doing? You may need to back up and regroup with some help.
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn
Thanks for the drawings and response. I am sure I will need some help. After looking at these drawings I can see my wiring is jacked up.
The drawing of the main switch doesn't match my switch exactly. I don't know how important that is. See photo of my switch below. The circuit drawing doesn't match my switch exactly or the main switch drawing either. My switch doesn't have the No. 2 terminal as shown on the circuit drawing and has an extra terminal, No. 8. which the main switch drawing doesn't have.
Not having terminal No. 2 as shown on the circuit diagram obviously will not allow the wire running from the No. 4 terminal (power) to the No. 2 terminal as shown on the circuit drawing.
The tail light terminal (No. 5, which looks like it is two terminals actually since they are connected) going to the what looks to be the instrument panel dimmer doesn't make any sense to me either. It's probably just above my understanding of electronics.
I'm trying to find a good drawing of the rear wiring harnesses for the tail light assemblies to sort that out.
I can't do anything today but I will try to sort out some stuff using these diagrams later.
When you get ready I will help you. The two drawings are confusing but your switch is just like the one I posted. The schematic drawing of it is confusing because it shows the internal wiring inside the switch and it shows the built-in thermal overload circuit. Don't worry about the terminal numbers on the schematic drawing/circuit diagram. In the early years, the front park lights came on with the tail lights on the first pull out of switch and fronts go off on the second pull out when the headlights come on. You can wire it so they will do whatever you want. No problem.
The tail light wiring is very easy. Don't worry.
Are you installing a new harness? or are you just replacing a few wires to fix up the truck? If you have purchased a wiring harness, give us the part number and the vendor you bought it from. We can look up the instructions on line. That way we are talking the same language and wire colors.
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn
Yay! I got everything working. I think my headlight switch is faulty. As I mentioned in my original post the terminals designated for the tail lights and "horn" (5 and 6) had no power at any position at any switch pullout position. So I ran a wire from the headlight terminal on the switch to the tail lights. It worked! Seemed logical. Is there anything wrong with that? Will it draw too much load? If you don't see a problem with that I will just attach both wires to that terminal.
The tail lights now do not have a fuse except the built in thermal overload on the H/L sw. The horn does not get connected to the same terminal as the tail lights or headlights. Did you use my markings on your pic? If so, are they right?
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn
Will that built in thermal overload in the H/L switch be adequate to protect that circuit with the tail lights added to it? Maybe I should buy a new switch so I can hook it up properly or possibly add an in-line fuse in the tail light circuit. Would that help?
My horn isn't wired to the H/L switch. I just said horn because that was how you identified that terminal on the pic of my switch. It is one of the terminals that has no power, along with the tail light terminal.
I bought a new headlight switch. There still is no power to any of the terminals with the exception of No. 1 (parklights) and No. 2 (headlights) at any position of the headlight pull knob. I had to connect the tail light wires to the headlight terminal in order for them to work.
Does the headlight switch get power from more than one source? The wiring diagram I am using shows wires running from a junction box. I obviously have more wires to hook up but am not sure where this junction box is to locate these wires. Are they referring to the fuse block?
