Lights Switch Operation (1 Viewer)

[wchevron]

When I bought my '77 a few months back the headlights and dash lights didn't work. Been doing some other work to it and had a guy from work (former mechanic) take a look. Just got it back today and headlights are working. When I pull the Lights knob out, the gauge/dash lights were not coming on. Thought maybe they were all the way dimmed. Turned the knob switch counter clockwise and the gauge lights started to brighten. When I push the Lights knob in, the dash lights don't turn off, but the headlights do. Have to turn the knob all the way clockwise until i feel a click, then the lights go out. Is this normal. I figured when I pulled the knob out, to turn the running or headlights on, the dash/interior lights would come on?

 

[peesalot]

something is hooked up wrong or the guts of the switch are not right.

 

[Engineer8000]

Based on the schematic, this is not correct. The dash lights should be off when the knob is fully pushed in.

(courtesy of Mr. @Coolerman)

 

[Living in the Past]

Tail lights, parking lights, side lights, license plate light should all work with the interior lights in both positions other than off. The connection to ties these all together is inside the the switch. If the parking lights and rest with off the switch as they should then something wrong inside the switch terminal T ties everything but the headlights together. Do the headlights only work with the switch pulled all the way out? Do the other lights work with the middle and all the way out positions?

 

[wchevron]

With the switch pulled to the middle position, front and rear running lights are on. Pulled all the way out, the headlights come on. If I turn the knob counterclockwise, the dash lights come on and will stay on regardless of which position the knob is in. Off, middle, all the way out. Unfortunately when I bought the truck, the lights weren't working at all so not sure if my guy wired something wrong or bad switch light you mention.

 

[Living in the Past]

Unfortunately the connection for the interior lights and the other non headlights are a connection in the switch. It acts like the rheostat wire was moved from T terminal in the switch to one of the B terminals inside the switch. Next step would be to pull the headlight fuse and tail light fuse to determine which one other neither. Some where else doesn't made any sense since the rheostat is inside the switch. It's possible to rebuild the switch. But easier to just replace it.

Since these are NLA I would pull the switch from the dash and inspect for any possible hacks from a PO. Would take some work to run a separate power source to the interior lights. Moving the wire to the rheostat internally would be the better way to do it. But POs do crazy things. I was running a 78 light switch in my 68 for a long time. I managed to do this with moving wires around in the plug. Went back later to the original switch but still need to clean up the wiring.

 

[wchevron]

I actually have a spare switch. Was in a box with some other misc items when I bought the truck. I'll swap it out and see if it works. Wonder if the PO had the same issue and never got around to swapping the switch. Considering none of the lights worked when I bought it, its probably not too far off.