[big matt]

Hello. So i have a 73 grand am.
Issue 1 No headlights, but has parking, marker lights, ect. I probe the headlight socket with switch on, and all 3 terminals have power. One is a ground so i am lost there.
Issue 2, is none of the gauges in the rally cluster work, except for the tach. They do nothing.
Issue 3, i have no gauge illumination. The other lights in the dash work, like by the hvac, and so forth, but no cluster lights.
Issue 4, did these cars have a foot dimmer switch from the factory? This car has cruise mounted on the turn signal stalk, which also double functions as the high low beam switch. Like a newer car. Click it toward you to make high beams come on. . When i click high beams on, both turn indicators light up, like the high beam indicator.
I have checked fuses and all are working as they should. I dont even know where to start here. Any advice is helpful

[Stuart]

The dimmer switch incorporated into the turn signal stalk was standard, no foot switch. It's listed under standard interior features in the factory brochure: https://oldcarbrochures.org/United%2...and_Am-06.html I think it was the same across all GM cars that year, my mother had a 1973 Olds Cutlass with the dimmer switch in the signal stalk.

Generally, you rotate the headlight switch knob to dim or brighten the dash lights - make sure it's not turned all the way off.

[big matt]

Thanks for clearing that up. I figured these cars would have a foot switch.
The headlight switches dimming feature for the working dash lights does work as intended.

["QUICK-SILVER"]

Issue 1 and 4b "sounds like" what happens when the front lighting harness doesn't have the ground wire attached to a good ground. Wire could be broken, loose or not attached at all.

Issue 2 and 3 could be related. Poor connections at the harmonica connector or the printed circuit falling apart.

At least on F bodies... The tach has its own power wire that plugs in the back of the tach. So for it to work and other gauges not work is understandable.

Got to ask, Did this car come factory with ralley gauges or converted from lights to gauges? Wire pin-out in the harmonica connector is different between the two and can/will cause all sorts of problems.

Clay

[big matt]

The car was born with rally gauges. I will check into the headlight ground. But the only thing that confuses me on that, is why the ground wire at the headlight plug has power.

["QUICK-SILVER"]

Originally Posted by big matt

But the only thing that confuses me on that, is why the ground wire at the headlight plug has power.

That's what happens when parking light ground has no where to go.

Parking lights still light up by power going to ground through other bulb filaments, turn flasher, etc..

Clay

[Cammer-6]

the most overlooked connection is the grounds.
Connect to a verified 12v (+) source(battery + is best) and probe for a ground

[big matt]

Okay, thanks guys. I will start diving into ground checking. Have a great day. I will report back when i find something