Weird low beam issue...Help!!!

[spiDmang]

Hey guys,

my driver side low beam has been acting up. Whenever I turn on the low beam, the light output is VERY weak (almost like a city light). On top of that, the driver side high beam is also on and is also very weak??

I have no idea where to start. Also if I try and disconnect the high beam connection and turn on the low beams, the driver side won't work. The high beam has to be plugged in to get any type of light output

Any ideas??


P.s. fuses are good, bulbs are new. Would a faulty relay cause ONE low beam to act so finicky?!?

[e30austin]

I would stick another relay in there just for shits n' giggles. Can't hurt.

[iansane]

Bad ground on the low DS low beam?

[spiDmang]

Bad ground on the low DS low beam?

Are you referring to the ground that connects to the bulb? If not, does that ground connected somewhere in the engine bay?

[PNWDan]

Low beam and high beam relay are different. Has someone done the pin jumper between them to run highs and lows at the same time? If so, I would look there and the relays first. If not, it sounds like you have a short in the loop somewhere.

[iansane]

Are you referring to the ground that connects to the bulb? If not, does that ground connected somewhere in the engine bay?

Not necessarily at the bulb itself. I've seen many 4light systems that develop a bad connection to ground on one low beam circuit. The electricity travels wherever it can and you get ~12v to both the high and low beam and a really dim bulb on each, or a normal-ish low and a constant on dim high beam. Not staying this is definitely your issue, but it's worth looking into when you mess with the relays.

[spiDmang]

~12v to both the high and low beam and a really dim bulb on each, or a normal-ish low and a constant on dim high beam. Not saying this is definitely your issue, but it's worth looking into when you mess with the relays.

This is the exact situation I have. But I don't get any
Light output if I don't have the high beam hooked up. Should I look into new relays?

[iansane]

This is the exact situation I have. But I don't get any
Light output if I don't have the high beam hooked up. Should I look into new relays?

I'd go after the ground on the low beam first. It sounds to me like the ground is gone and it's using the high beam circuit as a ground. When the high is unplugged there is no where for the electricity to ground out and it doesn't work. You have a DVOM? Check continuity between the ground terminal on the low beam head light connector and the chassis/bad/strut bolt/any solid ground.

[spiDmang]

I'd go after the ground on the low beam first. It sounds to me like the ground is gone and it's using the high beam circuit as a ground. When the high is unplugged there is no where for the electricity to ground out and it doesn't work. You have a DVOM? Check continuity between the ground terminal on the low beam head light connector and the chassis/bad/strut bolt/any solid ground.

Ahhhhh...thanks for putting that into nooblish (English for noobs)...

So theoretically speaking, if I grounded the low beam elsewhere, the light should work?

[spiDmang]

I'd go after the ground on the low beam first. It sounds to me like the ground is gone and it's using the high beam circuit as a ground. When the high is unplugged there is no where for the electricity to ground out and it doesn't work. You have a DVOM? Check continuity between the ground terminal on the low beam head light connector and the chassis/bad/strut bolt/any solid ground.

This was exactly the issue. Thanks a bunch bud! Now I can drive at night for late night munchies!

[iansane]

Jackpot!