xkeots

Any idea what I missed? My dash lights went out. I took out my power probe 3 and put it on both sides of dash lights fuse and the lights came on. I opened the dash and pulled the multi wire plug from the headlight switch and put the power probe to every female wire in the plug. No dash lights. All other lights came on.
What am I missing to get my dash lights on with the headlamp switch? Fuse is good.
Thanks
Jax
1977 L-82

sullyman56

I know it's something simple, but could it be the headlight switch **** is turned clockwise so that the dash lights are off?

xkeots

Tried that and tried jumping every wire with my power probe 3. No lights except when I put power to fuse

xkeots

Any idea what color wire at headlamp switch is for dash lamps?
Jax

jimbo8125

when you pull the multi plug from the switch do you have a ground ?

xkeots

Tried that and tried jumping every wire by bypassing them with my power probe 3. No lights except when I put power to fuse

jimbo8125

sounds like no power to the fuse unless you add it. Is there power to the switch? The switch is after the fuse I think. When you jump the fuse is the switch on? Are you sure the fuse is good? I had short in one of the socket that would immediately blow the fuse, so i'd replace it and was sure it was good but as soon as I tried the light it blew but gaveno indication that it blew, just no lights.

jimbo8125

is there power berfor the fuse?

7T1vette

Bad fuse. From your first post, it sounds like you 'jumpered' the fuse with your tester "and the dash lights came on".

Swap out the fuse and see what happens.

Peterbuilt

The 'tail lamp' fuse sends power to the 'instrument' fuse.

65GGvert

If it happened exactly as you described, the only two options are:

Fuse blown (may not be visibly blown, but separated at the cap internally)
Loose or corroded contacts that hold the fuse.

As stated earlier, the voltage for the instr lamp fuse first passes through the tail lamp fuse, so make sure those are working.

xkeots

The fuse is new and has continuity on both ends. I have power at the headlight switch as all other lights go on with switch. Does anyone know what color wire comes off the headlight switch to the fuse? When I put power to either side of fuse the dash lights come on. So when I pull the headlight switch and turn the **** either way I get no dash lights.
Thanks
Jax

SwampeastMike

Do your tail lights come on?

In '79 a 16 gauge dark green wire from the headlight switch connector feeds the instrument panel fuse. Put power there to see if the lights come on. Also you should have power in the 18 gauge orange wire as it is the feed coming from the tail light fuse. If both these test as mentioned the problem must be in the headlamp switch itself. (I do presume that you've made certain that all connectors are intact and clean.)

xkeots

[QUOTE=SwampeastMike;1592838879]Do your tail lights come on?

In '79 a 16 gauge dark green wire from the headlight switch connector feeds the instrument panel fuse. Put power there to see if the lights come on. Also you should have power in the 18 gauge orange wire as it is the feed coming from the tail light fuse. If both these test as mentioned the problem must be in the headlamp switch itself. (I do presume that you've made certain that all connectors are intact and clean.)

Orange I thought was power to interior lights?
I put 12v to every wire in the plug to the headlight switch after I pulled it off. Red and orange were hot

SwampeastMike

I believe that orange wires are fused and always hot.

The red wire in the plug is unfused hot that powers only the headlamps. The orange powers the "parking" lights and is fused via the tail lamp fuse.

If the instrument lamps don't come on when you put +12V to the dark green wire in the headlamp connector (IP fuse installed of course) yet they do when you put +12V to either side of the fuse then it sounds like a break in the wire between the headlamp connector and the fuse box. To verify test for continuity between that green wire and both sides of the fuse hole (fuse removed). You should get continuity through one of them.

xkeots

Tail lights are fine

xkeots

[QUOTE=xkeots;1592839360][QUOTE=SwampeastMike;1592838879]Do your tail lights come on?

In '79 a 16 gauge dark green wire from the headlight switch connector feeds the instrument panel fuse. Put power there to see if the lights come on. Also you should have power in the 18 gauge orange wire as it is the feed coming from the tail light fuse. If both these test as mentioned the problem must be in the headlamp switch itself. (I do presume that you've made certain that all connectors are intact and clean.



Here it is. I opened the dash. With headlight switch off (pushed in) I am getting 0 v on green wire plugged in, With switch pulled out, I am getting 11.9v (didn't check where the **** rheostat is) on the green wire in the plug. Using power probe 3, on 12v to both sides of fuse, I get dash lights. If I put 12v to the grey wire dash power plug next to the dash fuse, I get dash lamps. I am not getting power from the green wire to the grey wire/plug on fuse box. Do I have to pull dash apart or is it a one wire thing that I can just splice a wire from green to grey to fuse box power? I know that is the botch way. But I can't stay in that position due to my back.

Thanks
Jax
1977 L-82

SwampeastMike

[QUOTE=xkeots;1592857835][QUOTE=xkeots;1592839360]Unfortunately doing it the proper way means removing the dash and disconnecting the through-the-firewall connector at the fuse box.

But I see no real harm in just adding a wire (with in-line fuse) to the grey wire what feeds the dash lights.

xkeots

[QUOTE=SwampeastMike;1592859137][QUOTE=xkeots;1592857835]That's what I thought. Is the green wire only for the dash lights? If so, I will cut it and cut the grey wire and solder the grey wire to the green one with Heat shrink casing.
Thanks
Jax
77 L-82

SwampeastMike

[QUOTE=xkeots;1592859960][QUOTE=SwampeastMike;1592859137]Yes, it is only for the dash lights. Again, I would be certain to include an in-line fuse of the original rating of your IP fuse (probably 5-6A). If you don't a problem in the instrument wiring (common in these old cars) will take out your tail lights and potentially set something on fire behind the dash