When you pull the switch only the headlights come on..no dash, no gauges, no taillights. Removed the switch and replaced with new one same thing. Tested new switch with an ohmeter in closed(headlights on)position, between the power and the peg that activates headlights, 0 resistance as expected. Opened the switch(headlights turned off position) and resistance just as expected. Did the same on all the other pegs and got no response either way. However, when you connect directly the power to each one of the other wires in the harness each part lights up (gauges, tailights, etc.) Meaning that they all work fine. For the moment I put on a toggle switch between the power and the lights, gauges, etc so I don't get a ticket. Kind of important to light up the speedometer and all the gauges at night. My thoughts are that if a toggle switch works then everything else is working. It's the same thing just doesn't dim. Does this sound like I got a bum switch from parts dealer? Should the other "pegs" in the switch show 0 resistance when the switch is in the "on" position between the power (#1 peg) and all the other pegs? Or must a certain other wire in the harness have power or ground for the other pegs to show 0 resistance between the power and each peg? Any diagrams or experience welcomed. Thanks.

 

I'd check that all the wires are connected on the switch and all the fuses are good. Yes, a diagram would really help. If the switch is good, it sounds like the power source into the switch for those circuits is missing. Depending on where that power comes from, it could be a fusable link, bad wire, or even a bad ingnition switch.
Who's got a diagram here?

 

Red, I just went through this with my car, last year. I ended up taking a heavy gauge wire and jumping the switch. To my amazement, everything worked as it should. It's worked so well, I've left it that way. And I'll continue to do so, until the car bursts into flames and burns to the ground, at which point I'll have learnt the hard lesson. But until then, I'll enjoy my Bubba fix and the lights that go with it.

I too tried a new switch, back when I still believed in doing things the right way. But I had the same lack of success you are experiencing. So I don't really know what to do. And I obviously can't help.

See ya! :seeya

 

Have you tried checking resistance with the rheostat in various positions?? Do the interior light come on when the rheostat is rotated all the way clockwise (or is it counterclockwise, I don't remember)??

 

Looking at a wiring diagram for a 77, does any of your rear lights work.

ie: turn signals,licence plate light and reversing lights ??

As far as your gauges go, probably a fuse. To assist....

Look for a dk green wire that comes from the switch back to fuse box
this goes thru a fuse (8amp). A grey wire then leads back to the 5 illumination points for your guages.

There is a pink/black wire for gauges but Im picking thats the power for guage operation.

I cant see the tail light connection. Poss another fuse ??

20 amp fuse here orange wire with red heading off the other end.

Damn hard things to follow. :confused:

If its only tail lights that are out, its got to be a power issue which is prob fuse related.

Good luck as the fuse box is located so that you will need 16 inch fingers and three arms. :cool: :cool: :cool:

 

I'm pretty sure that the fuse for the dash / gauge cluster and tail lights are the same, it's to let you know you have no tail lights when the dash lights are out ( I think ). Anyway, just a suggestion, check that fuse.

Good luck!