Chevelles.com banner

1 - 12 of 12 Posts

·
Premium Member
Joined
·
152 Posts
Discussion Starter #1
Hey everyone! Car is looking great except a tiny problem I am currently having. I have a short somewhere in the headlight system, and the high beam bulb is getting about 1.4v, which is causing the high beam indicator to stay on no matter what as well as the middle lights to have just a tiny bit of light to them. I am officially at a loss for what to do. Here are the things I have tried...

Changed the headlight switch
Changed the floor dimmer switch
Checked all wiring to the headlights to make sure there were no touching wires
Flipped the polarity on the middle lights with the ground and high beam wire
Checked all grounds - all solid

Any other suggestions/ideas on what it might be? Thank you!


Sent from my Phone 2 using Tapatalk
 

·
Registered
Joined
·
1,536 Posts
This is one of those odd ones where you're going to have to really dig in. I'd start by disconnecting things until the light goes out, then figure out how they're tied together. Hows the underdash wiring look? Anyone been in there cutting splicing? I notice a bundle of loose wires where your a/c controls are supposed to go, might just need to go in and clean things up? Under hood, any wires close together or rubbing without loom to protect them?
 

·
Registered
Joined
·
2,410 Posts
A "short" is where a positive wire is connected to ground and it blows a fuse or fusable link so you don't have a short.

The splice for the ground wire is within one of the headlight sockets, it loops from one socket to the other.
 

·
Premium Member
Bill
Joined
·
1,222 Posts
I'm thinking one of the low beam head light bulbs has an internal short to it's high beam lamp. Unplug the low beam bulbs one at a time and see if the high beam lights and indicator goes out.
 

·
Registered
1970 SS 396 25-C, 1966 SS R-R
Joined
·
793 Posts
Will the factory wiring support the extra current draw of halogen lights.
 

·
Registered
Joined
·
2,410 Posts
Halogen lamps are usually the same wattage as the originals or 10 watts more per filament. Stock wiring should handle it.
 

·
Registered
1970 SS 396 25-C, 1966 SS R-R
Joined
·
793 Posts
I have a 71 Ford truck that someone put halogen lights in. A little while after turning on the high beams the headlights would trip the breaker and go out. I put relays on it to run the halogens. Just did't want the OP to have a melt down.
 

·
Premium Member
Bill
Joined
·
1,222 Posts
I have halogen lights in my Chevelle with 51 year old factory wiring. No problems here.
 

·
Registered
Joined
·
2,410 Posts
Stock wiring should handle it.
Cubsfan, if you don't mind a bit of aftermarket wiring on your car, there are headlight wiring upgrade kits available that run them right off the battery with heavier gauge wiring that has relays that get triggered by the original wires. I think it can be done without modifying or cutting into the original wires. This will make your headlights a little brighter because it eliminates the voltage drop in the thinner gauge original wires.
 

·
Premium Member
Joined
·
152 Posts
Discussion Starter #10
I'm thinking one of the low beam head light bulbs has an internal short to it's high beam lamp. Unplug the low beam bulbs one at a time and see if the high beam lights and indicator goes out.
I like this theory. I checked it it but still no dice.

Appreciate the ideas guys, it is American Autowire wiring so I'm not worried about voltage issues.

Yes, the wiring behind the dash is ugly. I still have a bit of cleaning to do back there for sure, the dash pad is just sitting on top and not screwed down yet. I'll take a look into that as well but I'm pretty sure the issue does not lie there.

Next step is to check at the fuse block. I'll hit the headlight switch harness with a multimeter as well, potentially the issue could be coming from there. This one is a real stumper...




Sent from my Phone 2 using Tapatalk
 

·
Premium Member
Joined
·
152 Posts
Discussion Starter #11
A "short" is where a positive wire is connected to ground and it blows a fuse or fusable link so you don't have a short.

The splice for the ground wire is within one of the headlight sockets, it loops from one socket to the other.
Poor wording here, I'm thinking maybe one strand of wire is making contact between the low beam and high beam positive somewhere maybe. Tracing the issue has been tough on this one.

Sent from my Phone 2 using Tapatalk
 

·
Premium Member
Joined
·
5,867 Posts
No short. You don't have a good ground to the low beams. The high and low beams share a leg on the ground circuit inside the outer bulbs. Since there is poor or no ground, the ground path is through the high beam filament, to the green wire, back through the dimmer switch to the high beam indicator filament to ground. As the power goes to ground, the bulbs light.

Pull all the connectors to the headlights and check for power at the green and tan wires. Hit the dimmer switch and the power should alternate between the green and tan. If they both light at any given time, then yes, the green and tan are connected somewhere. Disconnect at dimmer switch and use an ohmmeter to test the wire harness and dimmer switch . Green and tan should never connect to form a circuit.
694041


Make sure your headlight connector wires correspond to this picture.
694042
 
1 - 12 of 12 Posts
Top