Well, I've went over this here back in the summer. While my motor is off getting rebuilt I thought I'd try the panel again. I had pulled the standard 73 gauges from my Duster, replaced the bulbs, bought new bulb holders, replaced headlight switch, checked the circuit board for breaks, etc, and the old one had some broken pins..so I located some free parts, one being a circuit board with good pins..

Well I had reassembled that one with all the new parts, cleaned grounds and in it with with the screws grounding it to the dash. When i got it in and all together, I hit the light switch and my whole dash glowed with light. The Radio, A/C and gauges all worked..it was great. After a start of the car..Nothing..and I had nothing for a few months no matter how much I played with the headlight knob.

A friend gave me another board that was "good" And I have it right here and apart again. I popped the circuit board off with the lights in it and when i ground it, and tap the leads with a hot wire, the bulbs light up.

When I check power at the supposed lighting orange wire it should full voltage when I have the switch on.

I guess I'm confused as to what I need to do here..should i try another circuit board? Seems if this one works?

I've never had very good luck with these A-body instrument clusters. I'll admit the E-body system was better.

Sounds like the orig circuit board you went thru is working good & that only leaves power to it (the orange wires & they have fire) and the copper strip that grounds it, I'd trace that circuit for the open

Looks like I may have to look at my wiring diagram. I went ahead and stuck this back together and tested the metal shell/light panel for juice and it looks like I have it.

Ok i pulled it up, But I'd like to know if anyone can ID what this is in this section, i traces the orange back from the circuit board, it runs into what you see in the picture, circled in yellow:

The radio plug?

I think the pigtail/plug in to power the radio

I thought that but couldn't figure why they show 2 of them unless they are meant to be each other? lol I see that white wire somes out of there and it traces to the rear reverse lights(they work on my car)

I thought it was the male/female halfs that plug in to each other, those grey L shaped ones

I think i need to key the one that dims the whole dash, the radio lamp and Ac lamp included, they all went out with the dash lights after they initially worked when i "fixed" it the first time.

How does one bypass the dash dimmer? I know you do it at the headlight pigtail. I included a picture of the one in my car..

From what I can gather on the wiring diagram, the tan rheostat wire goes to fuse box, then back through the fuse to power the orange wire to the circuit board/radio lamp/light package pigtail

the pink wire on this headlight switch goes straight to the fuse box.

I unwrapped my wiring harness from fuse box over to the radio pigtail, I see all the locations of the orange feed wire. it all looks fresh and unbroken/uncut and nothing is pinched. Headlight switch is new, I have it out and it's making contact of the rheostat. I just wonder if a jump from pink-tan is the correct attempt to make?

I thought I'd add some more info, maybe I can help you help me pinpoint this, Like I said in the previous post, i unwrapped the harness wiring and traced the sources and destinations of the orange wires for the lights. It looks to me to be a little bit different than the 73 Wiring diagram..I'll post a picture here of my drawing and of the factory diagram.

Now here's the factory lay out, I have the lines colored and the area I'm in is the printer circuit board connector orange wire, traced back. it shows the feed wire to the circuit board as interupted by the radio pigtail..above post when i traced it carefully..it came staight from the fusebox, which that went from dimmer on the switch.

Hopefully I made it clear enough to see.

Check the grounds between the circuit board, the dash cluster, the cluster to the dash frame and the column to the dash frame.

I thought I'd add a little update to this post, I went out today witht he dash cluster still out, hooked up the battery and tied up the ammeter wires, clicked the headlight switch in and began some testing. I My fuse in the slot that supplies the dash lights kept showing good. As well as a tester on both terminals.. But i guess that doesn't prove everything, I wired a light into the pigtail for the cluster..no dice, i wired it to the headlight swtich tan wire..boom, light, well that runs to fuse box, oppostie the oragen feed wire..i test tan wire at box..boom, lights.
I test light opposite side on orange wire..nothing. I pull fuse, check it, its good. i stick it back in after a little cleaning of the clip that holds it..nothing.. i jump a piece of wire from tan clip, to orange clip..and check my light at the cluster pigtail..boom, light.

From what I can gather, the rivet that holds the clip for the orange side of the fuse is corroded and not making contact, when i checked my tester on that side, I wasn't holding in on the rivet, but the part that clips the fuse..i think the rivet is isolating my power. I may pop it out and replace whole clip or drill and re-rivet.

Wow.

You do realize that the dash grounds through it's mounting screws. In order for the lights to work you need to run a ground wire from the cluster to the body.

Yes, i do, when the cluster as screwed in it wasn't working. when i did my testing, I used the light i had as the dash, one wire attatched to dash frame, the other in the light feed wire that supplies power to the cluster.

When I had everything installed, I had the dash grounded via screws and even have a ground wire screwed the metal frame to dash cluster body.

The new headlight switch - is it brand new? Is there a good clean contact for its rheostat? What was wrong with the old switch? Tried swapping the old one back in as a test of the new one? And do you have a good ground between the steering column and the dash frame?