Low beam headlight problem

[Final Impact]

Originally Posted by markg8

Ok I used the probe I bought and have power to both hot wires on the L& R low beams. I did this by attaching the alligator clip to the body and sticking the probe in the hot wire connector on both sides and then again by connecting the a-clip to what I assume is the ground on the back of the bulb assembly too. Lights up all 4 times on both sides but still no low beam on passenger side.

Well that muddies things a bit. I'm trying to find a picture of what you're dealing with and can't find something thats 100% certain.

This is an H1 bulb yes? Is this what I should be seeing?
Xtec 6000K H1 and H3 Install "HOW TO"



So both sides are powered the same way. Both are grounded (you followed my test above), and you swapped the known GOOD bulb into the bad hole and it doesn't light?

If all the connections are good; then we have a CURRENT ISSUE! The test lamp draws maybe 0.50Amps and will light with very little energy applied. The 55 watt low beam is more like 4.0 amps or so I think. How long has it been this way?

OK - here is DETAILED instructions. Its unlikely that both the +12V supply and the Ground are bad. But one of them is limiting the current. The quick easy way is to run a ground wire from the battery to the lamps ground. DOES it light now? If so, we correct the ground.

If no, we need to find where we lost the energy. Have you tried swapping the relay and the fuses? Or pull them at look for corrosion or burns? It may come down to something in the fuse box. The next step for me would be seeing if the power from the fuse can actually light the 55W light. That would tell us its GOOD up to the fuse. Check or Replace the Relay first and report back.

Hint: 13V X 4.2A = 55Watts so the ground and the supply need to be able to pass at least 8 amps to initially light the light as it begins to glow the current drops.

[markg8]

Originally Posted by Final Impact

Well that muddies things a bit. I'm trying to find a picture of what you're dealing with and can't find something thats 100% certain.

This is an H1 bulb yes? Is this what I should be seeing?
Xtec 6000K H1 and H3 Install "HOW TO"



So both sides are powered the same way. Both are grounded (you followed my test above), and you swapped the known GOOD bulb into the bad hole and it doesn't light?

If all the connections are good; then we have a CURRENT ISSUE! The test lamp draws maybe 0.50Amps and will light with very little energy applied. The 55 watt low beam is more like 6.0 or 7 amps I think. How long has it been this way?

OK - here is DETAILED instructions. Its unlikely that both the +12V supply and the Ground are bad. But one of them is limiting the current. The quick easy way is to run a ground wire from the battery to the lamps ground. DOES it light now? If so, we correct the ground.

If no, we need to find where we lost the energy. Have you tried swapping the relay and the fuses? Or pull them at look for corrosion or burns? It may come down to something in the fuse box. The next step for me would be seeing if the power from the fuse can actually light the 55W light. That would tell us its GOOD up to the fuse. Check or Replace the Relay first and report back.

Hint: 13V X 4.2A = 55Watts so the ground and the supply need to be able to pass at least 8 amps to initially light the light as it begins to glow the current drops.

I didn't swap the bulbs, didn't understand that was what you were saying. Makes sense. I'll try it now but I'm pretty sure the new bulb is good. Actually the filament on the old bulb still looks good too. After I do that I want run a wire from the NEGgative post on the battery to the ground on the bulb?

[Final Impact]

Originally Posted by markg8

I didn't swap the bulbs, didn't understand that was what you were saying. Makes sense. I'll try it now but I'm pretty sure the new bulb is good. Actually the filament on the old bulb still looks good too. After I do that I want run a wire from the NEGgative post on the battery to the ground on the bulb?

I thought you did that already? Don't touch or leave finger prints on the bulb it will break it.

Bulb swap
Relay swap
Inspect fuses (remove them)

[markg8]

I just swapped the bulbs. The working bulb from the left doesn't work in the right socket. the new replacement bulb works in the left socket. I'm not touching the bulbs, only touch the bulb assembly from the back. I inspected the fuses and they are all good. Excuse my ignorance but what are you describing as the relay I should test? BTW the pics you posted look like what I have. The second pic of the whole headlight assembly looks like a left side. Now I want to run a wire from the NEGgative or the POS post on the battery to the ground on the right bulb?

[Final Impact]

Originally Posted by markg8

I just swapped the bulbs. The working bulb from the left doesn't work in the right socket. the new replacement bulb works in the left socket. I'm not touching the bulbs, only touch the bulb assembly from the back. I inspected the fuses and they are all good. Excuse my ignorance but what are describing as the relay? BTW the pics you posted look like what I have. The second pic of the whole headlight assembly looks like a left side. Now I want run a wire from the NEGgative or the POS post on the battery to the ground on the right bulb?

First find the head light relay and look for another like it. I think there is only ONE for both so now it comes down to finding what side went bad; i.e. the ground or the power.

Yes, run a wire from the bat NEG to Lamp NEG and see if that helps.

[markg8]

"The quick easy way is to run a ground wire from the battery to the lamps ground. DOES it light now? If so, we correct the ground."

Again pardon my ignorance, but I'm not clear on this. I run a piece of wire from one terminal of the battery (neg or pos?) to the ground wire on the right side. Does what light now? The low beam?

[Final Impact]

Have you held the bulb out of the socket and tried to power it? Does it glow a tiny amount at all? With volt meter you could measure across it and know what was up. It would be handy!

[markg8]

Ok, ran wire from the neg post on the battery to the right side bulb ground, turned on the car and the headlights and the right side came on. Success! Or progress at least. Now what?

[markg8]

And when that bulb came on it was as bright as day.

[Final Impact]

Originally Posted by markg8

Ok, ran wire from the neg post on the battery to the right side bulb ground, turned on the car and the headlights and the right side came on. Success! Or progress at least. Now what?

OK - That simplifies things. . . the existing ground wire although good enough to light the test lamp is NOT good enough to run a load of 4+ Amps.

Before we take big step (replacing the wire) we need to have a schematic for YOUR CAR. Not mine. In the schematic I posted earlier, it shows the bulbs ground wire connecting to the chassis (body/ground). If this is true for your car, either the wire is NOT connected or its damaged. We need a path to ground but first we A) get a schematic for your car, B) someone chimes in that knows it goes straight to ground.

I suggest you follow either side from the lamp and CONFIRM they go to ground. Once confirmed, we replace the wire.

Does that make sense? Also - Good Job!