Topic: '75 shift indicator light messed up
in Forum: C3 Electrical
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Hi folks, my '75 shift indicator light is messed up. It's off when the car and lights are off; on when the lights are on but the car is off; both are correct.
Start the car and it is on when the car is on but the lights are off and off when the car is on and the lights are on. Both are wrong!
I had the console apart the other day to do some work on the HVAC controls; the light had been working correctly before that. What have I messed up? The HVAC and lighter socket lights are working correctly as are all other dash and exterior lights. HELP!
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Build Date: May 7, 1975. 383 w/267 RWHP/310 RWTQ
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Lifetime MemberModerator
Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
Yer right...that IS messed up! 
I been pondering this one, and I ain't gotta clue. My only thought is that you might have mixed up the wires, or the bulbs while you had the console apart....
I been pondering this one, and I ain't gotta clue. My only thought is that you might have mixed up the wires, or the bulbs while you had the console apart....
Joel Adams
C3VR Lifetime Member #56 
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
I'm wondering if I've created a ground problem. 
Build Date: May 7, 1975. 383 w/267 RWHP/310 RWTQ
Lifetime MemberModerator
Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
VERY possible. It do kinda sound like a ground issue....
Joel Adams
C3VR Lifetime Member #56
My Link
(click for Texas-sized view!) NCRS
"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
OK, this is weird. Took the car to a cruze night tonight about 30 minutes from home. It was dark when it was time to come home. Start the car, turn the lights on and the indicator light comes on as it should. Get home, turn the lights out with the car still running and the indicator light goes out as it should. My wife is starting to call the car "Christine" as she's sure it's posessed. I'm just glad it fixed itself.
Build Date: May 7, 1975. 383 w/267 RWHP/310 RWTQ
Lifetime MemberModerator
Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
Stranger things have happened...
Joel Adams
C3VR Lifetime Member #56
My Link
(click for Texas-sized view!) NCRS
"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
It's doing it again...
Took the Vette for a long run out of town the other night. Getting dark on way home and turned on the lights and noticed the the shift light is out again and on when the lights are off, etc, etc.
Took the Vette for a long run out of town the other night. Getting dark on way home and turned on the lights and noticed the the shift light is out again and on when the lights are off, etc, etc.Build Date: May 7, 1975. 383 w/267 RWHP/310 RWTQ
OK, took the shift plate off tonight and noticed that there was a stray black ground wire. Turned the key on and the light came on. Touched the ground wire to the back of the metal shift surround plate and the light went out. Turned on the lights and the light came on. So...it's a ground problem like I was starting to suspect. I must of unscrewed it when I was working in there. A lot of the dash lights in these cars use the metal trim plates for a ground. Good to remember.
Build Date: May 7, 1975. 383 w/267 RWHP/310 RWTQ
Lifetime MemberHOWELL, NJ - USA
Joined: 5/18/2004
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Vette(s): 1979, Targa Blue (72 Color), Pace Car rear spoiler, L88 hood, Dark blue factory interior, 525HP 406, HD 700R4, 370 gears,Steeroids, composite rear spring, TT IIs wrapped in T/A Radials.
a loose ground will mess with ye every time!!!
Glad ya got it fixed!! 
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I think you are right on the money with the ground wires; the metal part of the dash also act as a ground for some of the lights in the cluster and 1 near the shifter.
And if memory serves me right; you should find 2 ground wires behind the dash cluster; one specifically for the radio and another one for the whole cluster.
You can lightly sand the contact it is looks dirty.
in Forum: C3 Electrical
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