#1  
Old 09-10-2023, 07:54 PM
big matt's Avatar
big matt big matt is offline
Senior Chief
 
Join Date: Dec 2007
Location: N.E. Cleveland
Posts: 293
Default 73 grand am electrical problems

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

__________________
1970 Formula 400 4 speed
2006 Gto. Ls2/m6
1972 Gto 455ho/th400 post coupe
1973 Grand Am 400 4 speed
  #2  
Old 09-10-2023, 09:21 PM
Stuart's Avatar
Stuart Stuart is offline
Ultimate Warrior
 
Join Date: Apr 2003
Location: Minneapolis
Posts: 7,938
Default

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.

  #3  
Old 09-11-2023, 06:40 AM
big matt's Avatar
big matt big matt is offline
Senior Chief
 
Join Date: Dec 2007
Location: N.E. Cleveland
Posts: 293
Default

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.

__________________
1970 Formula 400 4 speed
2006 Gto. Ls2/m6
1972 Gto 455ho/th400 post coupe
1973 Grand Am 400 4 speed
  #4  
Old 09-11-2023, 02:23 PM
"QUICK-SILVER" "QUICK-SILVER" is offline
Ultimate Warrior
 
Join Date: Feb 2008
Location: LaFayette Georgia
Posts: 5,523
Default

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

  #5  
Old 09-12-2023, 04:33 PM
big matt's Avatar
big matt big matt is offline
Senior Chief
 
Join Date: Dec 2007
Location: N.E. Cleveland
Posts: 293
Default

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.

__________________
1970 Formula 400 4 speed
2006 Gto. Ls2/m6
1972 Gto 455ho/th400 post coupe
1973 Grand Am 400 4 speed
  #6  
Old 09-12-2023, 05:18 PM
"QUICK-SILVER" "QUICK-SILVER" is offline
Ultimate Warrior
 
Join Date: Feb 2008
Location: LaFayette Georgia
Posts: 5,523
Default

Quote:
Originally Posted by big matt View Post
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

  #7  
Old 09-12-2023, 06:05 PM
Cammer-6 Cammer-6 is offline
Ultimate Warrior
 
Join Date: Jan 2004
Location: central Fla
Posts: 8,546
Default

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

__________________
Everything comes and goes
Pleasure moves on too early
And trouble leaves too slow
  #8  
Old 09-15-2023, 06:45 AM
big matt's Avatar
big matt big matt is offline
Senior Chief
 
Join Date: Dec 2007
Location: N.E. Cleveland
Posts: 293
Default

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

__________________
1970 Formula 400 4 speed
2006 Gto. Ls2/m6
1972 Gto 455ho/th400 post coupe
1973 Grand Am 400 4 speed
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 03:35 AM.

 

About Us

The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.

 




Copyright © 2017