Where's the Ground???
Thread Starter
2nd Gear
Joined: Sep 2008
Posts: 2
Likes: 0
Where's the Ground???
Hello all!! I am Paul a newbie corvette owner from flint MI.
My corvette is a 1976 Stingray L48 which sat for 17 years in my Uncles dirt Floor garage. I know I can hear the sighs. Anyway I was "lUCKY" to get it in a swap. I built a new garage 4 him and i got the Vette. I have limited car knowledge but consider myself fairly capabable of most jobs given they do not require specialty tools. I started out changing the front wheel bearings and replacing the Rotors and Calipers. After getting it on the road to test I found that my U joints and rear bearings were shot........$3000 later I am back on the road Thanks to Bairs Corvette in Penn. (Great work!!!!!!!!!!) My problem now is that I do not have Strong rear lights, NO blinkers and my fuel gage flips to full every time I hit the brakes. I have re attached two grounds on the rear frame but still have the same problems. Can anyone suggest an area to look for hidden grounds or a "Master ground/Harness" that could be causing the problem???? Oh Yeah My tach is stuck at 3100. Ground also????
Thanks in advance for any responses!!!!
pspeck
My corvette is a 1976 Stingray L48 which sat for 17 years in my Uncles dirt Floor garage. I know I can hear the sighs. Anyway I was "lUCKY" to get it in a swap. I built a new garage 4 him and i got the Vette. I have limited car knowledge but consider myself fairly capabable of most jobs given they do not require specialty tools. I started out changing the front wheel bearings and replacing the Rotors and Calipers. After getting it on the road to test I found that my U joints and rear bearings were shot........$3000 later I am back on the road Thanks to Bairs Corvette in Penn. (Great work!!!!!!!!!!) My problem now is that I do not have Strong rear lights, NO blinkers and my fuel gage flips to full every time I hit the brakes. I have re attached two grounds on the rear frame but still have the same problems. Can anyone suggest an area to look for hidden grounds or a "Master ground/Harness" that could be causing the problem???? Oh Yeah My tach is stuck at 3100. Ground also????
Thanks in advance for any responses!!!!
pspeck
Drifting
Joined: Aug 1999
Posts: 1,468
Likes: 1
From: Kirkland WA
I can only be partially helpful.
The TACH is mechanical - meaning there is an actual gear on the distributor that uses a "speedometer" like cable and connects to the back of the tach housing. It's not a really hard job to replace the cable. Just make sure you re-clock your distributor to the 9 o'clock position (if looking from above). This makes the cable easier to install and last longer.
You might want to check ground at the battery cable for the beginning of your ground search. That cable connects to the frame right under the battery tray. More than likely you have a loose ground or a loose connection on the back of your gauge cluster causing the problem. Get yourself a good wiring diagram (many vendors sell them laminated) and invest in the factory service manual or a reproduction! It's great to have!
The TACH is mechanical - meaning there is an actual gear on the distributor that uses a "speedometer" like cable and connects to the back of the tach housing. It's not a really hard job to replace the cable. Just make sure you re-clock your distributor to the 9 o'clock position (if looking from above). This makes the cable easier to install and last longer.
You might want to check ground at the battery cable for the beginning of your ground search. That cable connects to the frame right under the battery tray. More than likely you have a loose ground or a loose connection on the back of your gauge cluster causing the problem. Get yourself a good wiring diagram (many vendors sell them laminated) and invest in the factory service manual or a reproduction! It's great to have!
Safety Car
Joined: Apr 2000
Posts: 3,802
Likes: 61
From: Wichita KS
Hello all!! I am Paul a newbie corvette owner from flint MI.
My corvette is a 1976 Stingray L48 which sat for 17 years in my Uncles dirt Floor garage. I know I can hear the sighs. Anyway I was "lUCKY" to get it in a swap. I built a new garage 4 him and i got the Vette. I have limited car knowledge but consider myself fairly capabable of most jobs given they do not require specialty tools. I started out changing the front wheel bearings and replacing the Rotors and Calipers. After getting it on the road to test I found that my U joints and rear bearings were shot........$3000 later I am back on the road Thanks to Bairs Corvette in Penn. (Great work!!!!!!!!!!) My problem now is that I do not have Strong rear lights, NO blinkers and my fuel gage flips to full every time I hit the brakes. I have re attached two grounds on the rear frame but still have the same problems. Can anyone suggest an area to look for hidden grounds or a "Master ground/Harness" that could be causing the problem???? Oh Yeah My tach is stuck at 3100. Ground also????
Thanks in advance for any responses!!!!
pspeck
My corvette is a 1976 Stingray L48 which sat for 17 years in my Uncles dirt Floor garage. I know I can hear the sighs. Anyway I was "lUCKY" to get it in a swap. I built a new garage 4 him and i got the Vette. I have limited car knowledge but consider myself fairly capabable of most jobs given they do not require specialty tools. I started out changing the front wheel bearings and replacing the Rotors and Calipers. After getting it on the road to test I found that my U joints and rear bearings were shot........$3000 later I am back on the road Thanks to Bairs Corvette in Penn. (Great work!!!!!!!!!!) My problem now is that I do not have Strong rear lights, NO blinkers and my fuel gage flips to full every time I hit the brakes. I have re attached two grounds on the rear frame but still have the same problems. Can anyone suggest an area to look for hidden grounds or a "Master ground/Harness" that could be causing the problem???? Oh Yeah My tach is stuck at 3100. Ground also????
Thanks in advance for any responses!!!!
pspeck
Every taillight has it's own ground connector but they are wired together. Fix the ground problems before attempting the turn signals.
Always remember that Corvette bodies are fiberglass therefore no body ground. Every electrical item needs a ground wire.
For the turn signals start with the flasher which is under the passenger lower dash pad. Also check the fuse panel which is way up under the dash in the upper left corner of the driver side on the firewall.
Your gas gauge is also likely to be a ground problem from the description you gave.
Afraid I can't help with the tach.
cc
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
A 'metal' bodied car is 'grounded' everywhere because the frame and body are all electrically linked. The Corvette is a plastic body (non-conducting) with a metal frame; so 'ground' is transfered differently than most cars. Generally, there are frame-linked ground cables which connect electrical ground to the different areas of the car (to engine, to starter, to interior, etc.). From those points, there are solid black colored wiring that runs ground to all individual point requiring them (lights, instruments, radio, lighter, etc.). You need to purchase an Assembly Instruction Manual (known as the AIM) for your year Corvette. It shows all of the grounding cable locations. You also need an electrical schematic for your car; I like the Chevrolet Chassis Service Manual (year specific). Most Corvette parts places have both.
Burning Brakes
Joined: May 2005
Posts: 1,145
Likes: 5
From: South of London, Engerland
I think I counted four earthing points between body and chassis when I took the body off my '76.
1.
Main battery earth under the battery near the diff. (If this is bad then nothing should work.)
2.
Main starter motor/engine earth between engine block and passenger-side engine support chassis bracket. (Bad earth here means engine wouldn't start, no headlights, no wipers etc.)
3.
Small earth lead from driver's side #1 body mount to chassis, just behind the front wheel:
4.
Larger earth for rear lights, aerial, gas tank etc. right at the rear of the chassis on the driver's side:
My guess is that the rear earth is dodgy.
When I bought my car the tach was also stuck. In my case it was simply because the tach wire wasn't plugged in to the distributor. Since then it's worked fine. If your problem isn't that then you might need a new tach circuit board.
1.
Main battery earth under the battery near the diff. (If this is bad then nothing should work.)
2.
Main starter motor/engine earth between engine block and passenger-side engine support chassis bracket. (Bad earth here means engine wouldn't start, no headlights, no wipers etc.)
3.
Small earth lead from driver's side #1 body mount to chassis, just behind the front wheel:
4.
Larger earth for rear lights, aerial, gas tank etc. right at the rear of the chassis on the driver's side:
My guess is that the rear earth is dodgy.
When I bought my car the tach was also stuck. In my case it was simply because the tach wire wasn't plugged in to the distributor. Since then it's worked fine. If your problem isn't that then you might need a new tach circuit board.
Burning Brakes
Joined: May 2005
Posts: 1,145
Likes: 5
From: South of London, Engerland
The pass side engine mount is my number 2 above.
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6th Gear
Joined: Jul 2012
Posts: 6
Likes: 0
From: Tiverton RI
I also have a grounding problem on my 76 corvette.. I have checked the rear grounding point and it seems fine...My turn signals do not blink......new flasher..but when I turn on my left signal, my console light comes on.........................Help......... ...is there another ground point on the rear that I am missing?????????????????????
Drifting
Joined: Oct 2005
Posts: 1,527
Likes: 148
From: East London/SW Essex UK
Black Wire Disease was a problem with model aircraft radio control equipment that used to affect the copper stranded cable feeding the servos - whilst the cable is intact the internal resistance once 'black wire' had set-in was sufficient that the servos wouldn't function. I was surprised when the earth tails from rear lamps to chassis on my '68 (when I first got it) had exactly the same problem - only after replacing the tails and opening them-up the could you see the corrosion - the copper was almost crystaline!
Le Mans Master
Joined: Aug 2006
Posts: 7,423
Likes: 1,558
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
Hi and welcome!
See post 7 to check if the socket has a good ground.
http://forums.corvetteforum.com/c3-g...n-signals.html
Here's a schematic.
http://www.vetteprojects.com/bmv/mis...tte%201976.pdf
See if this helps a little.
http://forums.corvetteforum.com/c3-g...n-signals.html
Here's a schematic.
http://www.vetteprojects.com/bmv/mis...tte%201976.pdf
See if this helps a little.
Team Owner
Joined: Jun 2000
Posts: 38,923
Likes: 1,481
From: Southbound
Cruise-In II Veteran
Safety Car
Joined: Mar 2007
Posts: 3,652
Likes: 49
From: Bridgewater nj
Electric gremlins suck and you must have been looking for awhile to pull this thread up from 5 years ago.
I would check the head light switch after all your sockets are checked.
There is also a wire harness bend located behind the front drivers side head light that is know to have wires breaking and shorting problem. Not sure if its all C3 but I know my 82 needs a wiggle every now and then. One day I'll fix it hopefully before I burn it to the ground
I would check the head light switch after all your sockets are checked.
There is also a wire harness bend located behind the front drivers side head light that is know to have wires breaking and shorting problem. Not sure if its all C3 but I know my 82 needs a wiggle every now and then. One day I'll fix it hopefully before I burn it to the ground
