One headlamp brighter than the other.

[Lmarche]

Hi, when I bought my 911sc 1982, I noticed that one headlamp low beam was brighter than the other. Changed the bulbs, exchanged the fuse's, cleaned the headlamp essembly and cleaned the bulb terminarls with contact cleaner, but the problem remains, one low beam reflects white light and the other looks bright yellow.

I recently updated the headlamps from H4 US spec to european. Hi beam light are the same intensity.

Any idea where to start tracking the problem, Thanks for any help.

[Jim Richards]

Measure the voltage at the socket for each headlamp. Perhaps one isn't getting full voltage.

[DRACO A5OG]

Originally Posted by Jim Richards

Measure the voltage at the socket for each headlamp. Perhaps one isn't getting full voltage.

+1

consider getting the headlight relay cheaper than a new stalk.

[BernieP]

Bad ground on one side.

Bernie P

[zippy_gg]

I would suspect corrosion at the various wire terminals, including the headlight socket.
In addition to the suggested relays I would suggest cutting the wires a bit (and I bet you'll see green) and re-cripping to eliminate the resistance from oxidation.

[LjH]

Check and clean the ground connections. Get to bare metal, use bulb grease on the body and add a star washer.

[kidrock]

I wonder if the problem is just one of the bulbs slowly going bad?

[LjH]

Originally Posted by kidrock

I wonder if the problem is just one of the bulbs slowly going bad?

Swap the bulb with the other side and see if the problem moves.

[rnln]

swap bulbs back and forth?

[LjH]

Yes. If it is the bulb the problem will move. If not then it is most likely a bad ground or bulb socket.

[timmy2]

Euro H4 lenses now?
Are both glass lenses new?
My car has one original lense and one new one, the old one looks a little yellow compared to the new one.
Do you see the same color difference with the lamps turned on and the lamp fixture removed?

[Lmarche]

This is My first 911. Where's the ground for the headlamps attached?, I already swap the bulbs but without luck. Is it necesary to install relays for H4 headlamps? And if they where installed by the previous owner, where's the usual place to find them?
Thanks for all the feedback.

[LjH]

Check the link below
One of the wires on the pigtail goes to ground the other two wires are high and low beams. Someone else may be able to provide the colors. Once you identify ground you can run it back till it attaches to metal and check the connection. Alternately you could run another wire to the body.

Pelican Technical Article: H4 Headlamp Upgrade - 911 (1965-89) - 930 Turbo (1975-89)

[Lmarche]

While tracking the ground for the less bright headlamp, I found that someone rewired the cables with thinner caliber, at least for the ground. This could be it? Right?
Thanks for the help guys.

[DRACO A5OG]

possibly but to be sure get the voltage readings

[Lmarche]

You are right Draco. Tomorrow I'm buying a voltmeter to check not only the ground but the yellow wire (+) for the right low beam. I rechecked the hi beam and low beam intensity and the problem is only on the right low beam ( the wire diagram shows a shared ground for hi and low beam). So tomorrow I'll test the votage at the bulb conector and the fuse. Maybe that way I can track the damaged part of the cable.

[bgqkeneg]

Get to bare metal, use bulb grease on the body and add a star washer.