Before we start, yes, i have a 73 Plymouth Valiant electrical diagram.

http://www.mymopar.com/downloads/1973/73ValiantA.jpg

http://www.mymopar.com/downloads/1973/73ValiantB.jpg

I have what seems like the essentials + some headlights/taillights with dimmer, brake lights, turn signals, license plate light. cigar lighter, wipers. hazard lights glove box and dome light (although dome light and glove box light work when the other is off.)

what I don't have: dash lights, gear selector light, ashtray light. Blower motor ignition relay light on steering column

What I have had, but don't for random reasons:
map light, horn, and the radio is very week.

Things I think it could be?
-Well I replaced the fuses in the fuse block. (5) 20A and (2) 3A

-I wondered if it was the headlight switch, they have went bad on me before, but it seems 90% of what is running right is coming from that switch.

-that little voltage regulator on the back of the gauge cluster

-wiring itself. I tend to doubt it, I'd had it all out, very clean, no corrosive connections, all very secure.

anything else?

Just for kicks hook up a jumper from good clean metal on the dash to a good ground on the body or direct to the battery - terminal and see what happens.

The voltage limiter for the gauges on the back of the dash has nothing to do with the lights. Sounds like the dash light rheostat part of the headlight switch is bad.Use a test light to check for power at the dash light fuse. It is fed by the headlight switch. If it brightens and dims from the HL switch you can rule out that switch.

I'm with Stumpy on this one. it's got to be the switch or a ground issue. Check the grounds for the switch and instrument panel.

I'll check that ground thing..see what happens.

I guess it puzzles me since I had this WHOLE dash frame out a year ago, and the part of the harness that screw to the dash I made sure was clean! I'll check it again though...i even checked the ground wire on the steering column to column mount..

I'd like to have another headlight switch anyways, this one I have used before but the button when off is way to far in.

I'll check that fuse for power though.

I thought of the switch but he says that the radio is dim (thinking volume)on AM. That is what suggested ground to me.

I assumed the light on the radio was dim.

If you had the whole dash frame out, did you paint the interior of the car purple when you painted the rest of it? If you did, and then painted the dash frame before you reinstalled it....I'd say it's a grounding problem. I always leave clean shiny metal under the bolt where the bottom feet of the dash frame bolt up, both on the body and the dash frame. I use a little silicone grease at that point also. Make sure the column has a good ground also.

good thought on the purple body and dash frame, I'll check that out..

On the radio, no light at all. The audio on the radio is there but very faint.. I literally had my ear against it before I could hear it and even then I couldn't make out what was going on a local station we have.

the ashtray light under it isn't working either, as a test to make sure I'm not crazy, i unplugged it and tested it on a battery...it lite up nice and strong..

but like suggested, I'll so some ground tests on that dash frame tomorrow..thanks for the ideas guys.

Yes it does sound like an open ground. I will always add as many grounds as possable to everything. Like three from the engine, one from the battery to the head, one from the altanator to the frame and one from the head to firewall, All 6 ga except the battery is a 4 ga. I also add a 10 ga from the battery to the firewall. Under the dash I add two 10 ga grounds strapped from the firewall to the Dash frame.

for starters i pulled the small screw that holes a little ground wire to the passenger side of dash, sanded the surface of the dash, cleaned the eyelet and the screw, used di-electrical grease, put it back in snug.

the 2 bolts along the bottom of dash frame i pulled, cleaned up with sandpaper, cleaned body surface and dash tabs, used the grease and tightened them both down.

Checked ground strap on engine, greased and tightened it on head and inner fender. and the battery-head on the front as well.

Unfortunetly, no change. Should I try ground wires or are there some other present grounds I should check?

I would get rid of all your grease. Where you are using it IMO should be put together dry for a good contact.

under the washer area of the bolt.

IMO that is a large portion of the contact area.

ok I'll clean it off and see what i get..

Unplug the power feed plug from the not working item (radio,etc) and test with a meter or grounded test lamp. I have made test lamps from a side marker socket with extended wires, an alligator clip, and a nail crimped into a butt connector. If power is low, trace back and retest at other plugs, switches, bulkhead connector, etc on the same circuit.

i cleaned those ground contacts of grease, still nothing, I remembered I have the 73 owners manual laying around, found it and took a look at the fuse block. on my (5) 20 Amp fuses, I am getting 12.5ish on my voltmeter, my test light glows on each side of the fuse.

the (2) 3Amp fuses I don't pull a glow on the light. I guess thats normal right?

What confuses me is what it has listed for each one.

Circuit 1: Rear defogger/A/C clutch (full 12v)
(I have no defogger and I haven't the A/C hooked up yet.)

Circuit 2: A/C blow motor (full 12v)
(if thats my blower motor mounted on the firewall..it does nothing.)

Circuit 3: Radio, Back-Up Lamps, Reverse Gear Ind. Lamp, turn signals,

(I have automatic so no reverse indicator lamps.. the rest work except the MAP light, which DID work but doesn't now, my tester pulls like 0.10 at the most of the 2 way connector. it feeds the glove box which works unless you hit the map light switch, it nearly kills the glove box light while it's on.)

Circuit 4: Cigar lighter, Dome lamp, Trunk lamp, stop lamps, map lamps, glove box lamps, Ignition Lamp, Hazard flasher

( All these work except the MAP light, which DID work but doesn't now, my tester pulls like 0.10 at the most of the 2 way connector. it feeds the glove box which works unless you hit the map light switch, it nearly kills the glove box light while it's on.) and my ignition light doesn't work)

Circuit 5: Tail lamps, license plate lamp, parking lamps, instrument lamp, side marker lamp, horn, key in buzzer

these all work except instrument lamp. the horn way working, but not just clicks when I hit it...

Circuit 6: Brake warning lamp, fuel gauge, temp gauge, low oil lamp, seat belt light and buzzer

not positive on all these yet.

Circuit 7: Instrument cluster lamp, radio lamp, gear selector lamp, ash tray lamp, A/C control lamp,

(i thought tinstrument lamp was already covered in 5 but it has it listed again, it doesn't work, in fact none of these work.)

I'll do further testing, although my electrical knowledge it a bit shallow.

On #7 your test light should get brighter and dimmer when you turn the headlight switch knob with the lights on. If it doesn't then you have a bad HL switch.

i like those type of tests Stumpy, nice and simple, i give it a try here in a bit..thanks

On the horn: go out and try to tap it with a hammer and try shake the contacts. Also there should be a star shaped adjuster on the outside of the horn try to turn this.

I usually find grounding is the most often reason for such problems - and it's easiest to find out.

Using a "jumper-cable". Connected directly to battery -. Long enough to the cabin. Use a sharp screwdriver at the end to make contact. Grab through paint to reach metal. And just try if it changes if you contact dash frame or columns frame or body.

This is not the repair but you should make sure if it's a grounding problem or not.

If not, you can do the same on the +-side. Connect jumper cable to battery + and contact fuses holder.

Get a DVOM and do a voltage drop test on both the + and - sides.

http://www.engine-light-help.com/voltage-drop.html

BTW, can the headlight switch be this problem? and can it cut out a whole 1-2 circuits?