Lighting issues. Plz Help
Thread Starter
Racer
Joined: Jul 2004
Posts: 400
Likes: 1
From: California
Lighting issues. Plz Help
i got a 79 vette with serious lighting issues. basically when i installed a new headlight switch, the high beams would turn on (they are stuck on) but the low beams wouldnt even work. then a few days ago when i had the tranny rebuilt the exterioir lights stopped working except for the headlights. then my interioir would work when i hit the brake with the car off....In Short....
WHERE IS THE GROUD FOR THE LIGHTS?
is it somewhere on the outside, or is it inside the car? i think i may have moved something causing it to have a short, or i just have a really rusty conenction on the ground casuing it to go intermintent.
WHERE IS THE GROUD FOR THE LIGHTS?
is it somewhere on the outside, or is it inside the car? i think i may have moved something causing it to have a short, or i just have a really rusty conenction on the ground casuing it to go intermintent.
Thread Starter
Racer
Joined: Jul 2004
Posts: 400
Likes: 1
From: California
Still Cant find the ground for the lighting system in my 79'. i have a bad leak coming from the driver side somewhere and its running into the cockpit and shorting something out where the ground is i think.
Drifting
Joined: May 2003
Posts: 1,634
Likes: 2
From: Melbourne, Victoria, Australia, the World
First place to check is the chassis next to the battery. this where all the current in the car flows back to the battery. the cable comes out of the battery box and terminates on the chassis. This is underneath the car.
Next check the ground at the engine. The cable goes from the chassis at the engine mount to the block and is usually held on to the block with one of the engine mount bolts.
There is a ground which comes off the starter mounting bolts and feeds into the loom. On the 68 this feed is for the wiper motor and blower only.
The headlights ground is usually bolted to the front of the radiator support panel.
the rear lights ground is bolted to the chassis on the (drivers?) side.
Make sure all of these are clean and make good contact.
Hope this helps.
Next check the ground at the engine. The cable goes from the chassis at the engine mount to the block and is usually held on to the block with one of the engine mount bolts.
There is a ground which comes off the starter mounting bolts and feeds into the loom. On the 68 this feed is for the wiper motor and blower only.
The headlights ground is usually bolted to the front of the radiator support panel.
the rear lights ground is bolted to the chassis on the (drivers?) side.
Make sure all of these are clean and make good contact.
Hope this helps.
Pro
Joined: Sep 2002
Posts: 620
Likes: 2
From: San Antonio TX
When I got mine, it looked like a rats nest under the dash. Serious "bubba" wiring fixes had been performed. The wiper switch was bad, so it had been bypassed. The stereo was some cheapo aftermarket that had been grafted into the wiring with complete disregard for anything.
It was a mess, and there were countless electical gremlins.
I ordered a wiring diagram and started going through one system at a time.
It was a real PITA, but it all works now.
The wiring diagram is a great investment and will save you a lot of time and grief in the long run.
Good luck.
It was a mess, and there were countless electical gremlins.
I ordered a wiring diagram and started going through one system at a time.
It was a real PITA, but it all works now.
The wiring diagram is a great investment and will save you a lot of time and grief in the long run.
Good luck.
Drifting
Joined: Sep 2003
Posts: 1,325
Likes: 6
From: FRANKLIN GA
Team Owner
Joined: Aug 1999
Posts: 30,995
Likes: 98
From: Ontario
Here is the wiring diagram for the 1979 headlight circuit. The grounds for the lights are at the front of the car. The "fender support" is actually the rad support.
http://img.photobucket.com/albums/v1...circuit004.jpg
http://img.photobucket.com/albums/v1...circuit004.jpg
Last edited by Paul L; Jan 2, 2005 at 01:37 PM.
Race Director
Joined: Oct 2002
Posts: 12,065
Likes: 2
From: Smalltownville Michigan
Cruise-In 5, 6 & 10 Veteran
St. Jude Donor '09
I had a similar problem and it was corrosion on the fuse panel it self. I went to NAPA to get some fast drying electrical contact cleaner and toook the screws out of the panel and sprayed the back of it... put it back in and sprayed the front side... works fine now...
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Thread Starter
Racer
Joined: Jul 2004
Posts: 400
Likes: 1
From: California
Originally Posted by paul67
Here is the wiring diagram for the 1979 headlight circuit. The grounds for the lights are at the front of the car. The "fender support" is actually the rad support.
http://img.photobucket.com/albums/v1...circuit004.jpg
http://img.photobucket.com/albums/v1...circuit004.jpg
Thread Starter
Racer
Joined: Jul 2004
Posts: 400
Likes: 1
From: California
Originally Posted by Aflac
I had a similar problem and it was corrosion on the fuse panel it self. I went to NAPA to get some fast drying electrical contact cleaner and toook the screws out of the panel and sprayed the back of it... put it back in and sprayed the front side... works fine now...
jeez why didnt i think of that, oh byt he way where are the screws for the fuse panel?
Race Director
Joined: Oct 2002
Posts: 12,065
Likes: 2
From: Smalltownville Michigan
Cruise-In 5, 6 & 10 Veteran
St. Jude Donor '09
That sounds pretty familiar for the P/N... The screws are in the corners and they can be a royal pain to get started while standing on your head! I think if I have to do that again, i'm gonna pull the speedo out and go at it that way...
Team Owner
Joined: Aug 1999
Posts: 30,995
Likes: 98
From: Ontario
Drifting
Joined: May 2003
Posts: 1,634
Likes: 2
From: Melbourne, Victoria, Australia, the World
Grim,
You want the shop (service) manual as pictured above or the Assembly manual.
The service manual tells you how to repair things including the specifications and the Assembly manual tells you how they (were supposed to) put it together at the factory. Both will have the electrical diagrams.
The Service and Owner manual sounds like the little book the original owner received with the car telling them how to operate it.
You want the shop (service) manual as pictured above or the Assembly manual.
The service manual tells you how to repair things including the specifications and the Assembly manual tells you how they (were supposed to) put it together at the factory. Both will have the electrical diagrams.
The Service and Owner manual sounds like the little book the original owner received with the car telling them how to operate it.
Drifting
Joined: May 2003
Posts: 1,634
Likes: 2
From: Melbourne, Victoria, Australia, the World
Interior lights or dash lights?
The interior lights have a permanent volts applied and switch the earth at the door jamb switches. The interior switch on the light switch also switches earth.
The dash lights are fed volts via the resistor on the light switch (maybe different on later models). the instrument clusters have a ground wire attached and this ground is commoned before being attached to the birdcage. On my 68 the attachment point is on the hinge pillar on the drivers side. This is up behind the dash.
If you have no dash lights I would check the resistor in the light switch first. They have a tendency to go open circuit. If everything else is working (clock etc..) then the ground is there.
The interior lights have a permanent volts applied and switch the earth at the door jamb switches. The interior switch on the light switch also switches earth.
The dash lights are fed volts via the resistor on the light switch (maybe different on later models). the instrument clusters have a ground wire attached and this ground is commoned before being attached to the birdcage. On my 68 the attachment point is on the hinge pillar on the drivers side. This is up behind the dash.
If you have no dash lights I would check the resistor in the light switch first. They have a tendency to go open circuit. If everything else is working (clock etc..) then the ground is there.
Thread Starter
Racer
Joined: Jul 2004
Posts: 400
Likes: 1
From: California
i replaced the headlamp switch recently and then nothing worked still (dash lights, exterior excluding headlights) and out of the blue the interior lights started working on a cold wet night and it was a miracle, and now they dont work again, so im guessing the ground is very ad and has lots of rust. would it be suitable to find a better place to ground everything so i dont have to worry about moisture and leaks getting onto the ground?