9-7x right halogen low beam out

Harrisons

Original poster
Member
May 14, 2024
5
Ohio
To start, I’m working on a 2008 9-7x 4.2i. I can’t get the passenger Halogen low beam headlight to work. New bulb, new HDM relay, good fuse. The driver’s side works fine. The condition is the same with DRL and lamps fully on. I don’t see broken wires, corrosion, or melting at the connectors. With a multimeter, I have voltage across either black wire to the green/black wire, and nothing if I test either black wire to the white wire. If I read the diagram correctly, the white wire is positive voltage for the low beam.

Any ideas?
 

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mrrsm

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Perhaps... There is an issue with the Ballast (if present and part of the Circuit) ?

 

TollKeeper

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Dec 3, 2011
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Brighton, CO
With it being the 4.2, should be no ballast.

Have you tried swapping the low bulb to the other side to verify its not the bulb?
 
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Harrisons

Original poster
Member
May 14, 2024
5
Ohio
With it being the 4.2, should be no ballast.

Have you tried swapping the low bulb to the other side to verify its not the bulb?
I put a brand new bulb in, then tried the other bulb to be sure that the new one wasn’t defective.

And you’re correct, no ballasts.
 

TollKeeper

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Dec 3, 2011
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I would first start by verifying that both bulbs are indeed bad.

You can use direct current with wires to the battery, or pull the headlight assembly out from the other side, and try both bulbs in the low beam there.
 
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Harrisons

Original poster
Member
May 14, 2024
5
Ohio
I would first start by verifying that both bulbs are indeed bad.

You can use direct current with wires to the battery, or pull the headlight assembly out from the other side, and try both bulbs in the low beam there.
I have. Both bulbs work in the driver’s side unit. In fact, original bulb that I thought was bad works in the driver’s side.

My best guesses are that there’s an open circuit inside the right headlamp where I can’t see. Or maybe it’s not getting power to the low beam circuit. I was hoping that someone would be familiar with the plug that goes to the assembly. I’m not sure which wires are supposed to be hot in the plug.

I think that tomorrow I’ll pull the whole other assembly out and plug it in on the passenger side and see if it light up. Otherwise, I’m going to have to start chasing wires through the body. Which is never a good time.
 

TollKeeper

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Dec 3, 2011
8,177
Brighton, CO
Next is to test if power is making it to the plug at the back side of the headlight. Just requires a voltmeter.

First start at the plug that actually goes into the headlight.. Voltage?
Then check the plug that goes into the housing.. Voltage?
 

budwich

Member
Jun 16, 2013
2,075
kanata
The condition is the same with DRL and lamps fully on. I don’t see broken wires, corrosion, or melting at the connectors. With a multimeter, I have voltage across either black wire to the green/black wire, and nothing if I test either black wire to the white wire. If I read the diagram correctly, the white wire is positive voltage for the low beam.
??????

I think that's a "BIG IF" on the read of the diagram... :smile:

What white wire are you talking about? The only "WH" that are shown are connected to ground... as in "zero volts".

First, you need to check the fuses that are there... shown as fuse 6 and fuse 3. Not sure of your "fingers with a meter", so I would try swapping them to see if the problem follows. You can use your meter and look for voltage at those fuses and using the battery ground as reference.

NOTE: you can test for voltage at various points along the circuit path... again with the battery ground as the reference. You can cross checks your results against the working side.

Go from the results.

Barring a broken wire (which the tests may highlight), your next likely issue is the "sublayer" of the fuse box.... :smile:
 
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Harrisons

Original poster
Member
May 14, 2024
5
Ohio
??????

I think that's a "BIG IF" on the read of the diagram... :smile:

What white wire are you talking about? The only "WH" that are shown are connected to ground... as in "zero volts".

First, you need to check the fuses that are there... shown as fuse 6 and fuse 3. Not sure of your "fingers with a meter", so I would try swapping them to see if the problem follows. You can use your meter and look for voltage at those fuses and using the battery ground as reference.

NOTE: you can test for voltage at various points along the circuit path... again with the battery ground as the reference. You can cross checks your results against the working side.

Go from the results.

Barring a broken wire (which the tests may highlight), your next likely issue is the "sublayer" of the fuse box.... :smile:
“Fingers with a meter?” What are you saying? I have a voltmeter, it shows steady voltage across either black wire to the green high beam wire. The fourth wire in the plug, which is white (TN/WH on the diagram) has no voltage at any time.

What I haven’t done is compare the readings against the drivers side which is working. So thank you for the idea.
 

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