The left low beam on my 2003 350z won't light. It's HID. The fuse is good, I tried a new bulb, and swapped in another used ballast. Besides the other used ballast being bad, what else could it be? Connections look good. There was water in the headlight.

 

The connections may look good, but you can't be certain until you put a multimeter on it to verify continuity. Also, if there's water in the headlight, that makes me think the fender liner is either gone or not fitted correctly. It's possible some road debris could have caused a short or a loose connection somewhere. Another thing could be the HID igniter.

 

Thanks. The ballast came with an igniter so I swapped both. I haven't tried the new ballast with my igniter and vice versa. I, apparently stupidly, used my multimeter at the igniter and didn't get electrocuted. I think you're saying I need to test before the igniter. Yeah, there is no fender liner on this car and one of the tabs on the round cover is broken so not a good combo.

 

If you can, use a ballast and igniter that is verified and confirmed they work correctly. It sounds like the other side's components work properly, so you can use those. Or swap in the ballast and igniter on that side to see if they work.

I wouldn't be terribly surprised if the connections after the headlight connector (leading to the various headlight components) are bad/loose/shorted.

With your multimeter, first check the body harness connector with your multimeter. If those check out, test the connections after the headlight harness connector.

 

Thank you. When you say check, do you mean check for voltage with the switch on? I was hoping avoid removing the other headlight, but I've burned up so much time already I guess I should take the plunge.

 

Yes. Connect your multimeter to the body harness connector and then turn on the headlights from the switch on the stalk to verify you're getting 12 volts. To check for ground, select the appropriate setting on your multimeter and then connect the probe to the ground pin on the body harness connector. If those check out, then you need to probe the connections from the headlight connector harness and basically do the same procedure.

Or, alternatively, you can check for continuity between the pins on the harness connectors to verify that the signal is going through. If you get 0.L, then there is a break somewhere.

This is not the easiest to explain using words. Ha.
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I did these tests and found something, but not sure what to do next. The continuity of the wires from the main headlight harness connector to the ballast is good. I then tested the voltage on the other side of the main headlight connector with the headlight turned on. The readings were around 2 volts. I did the same test on the right side and the readings were 12 volts. So for some reason, some, but not enough voltage is getting to the pin on that left side headlight connector. I don't know much about electricity, but it seems odd to me that it would be low and not just zero or 12. Any suggestions for what to check next? Appreciate the help with this!

 

Sounds like possibly the connector is the issue since you're getting a LOT if voltage drop on either side of it. It could be due to bunch of gunk or corrosion since there weren't any fender lines. You could try using an electronic parts cleaner, or just get a new connector and splice it in there or re-pin the wires.

If you're replacing the connector anyway, you can confirm by unpinning the wires and connecting them or using a jumper wire which bypasses the connector.

 

Today I tested at the fuse and got 12 volts there. I then retested the left headlight connector voltage and got 12 volts. It's very difficult to get a reading there because the probe doesn't fit well in the connector holes. I think the low readings I was getting before were because I was not getting a good connection with the multimeter. I bit the bullet and removed the bumper entirely and swapped the ballast and ignitor from right into left and vice versa. Now the left works and not the right. Thus, it's the ballast or ignitor. I guess it's just bad luck that the set I had in the left headlight and the set from Ebay are both bad. I tried all the combinations of the left and Ebay ballasts/ignitors and nothing worked. At this point, I'm just going to buy another set off Ebay or maybe a reconditioned set from Z1M. I think there are two lessons here. One, just bite the bullet and swap the ballast/ignitor from a known good headlight right off the bat. I didn't want to remove the entire bumper and other light but it's wasn't that big of deal. Two, make sure you're getting good data with your multimeter! Thanks for your help.

 

That sucks. If you have a 12v power supply or a verified HID bulb that works, you can always test the ballast and igniter by connecting the two pins on the ballast to the 12v power source and see if the bulb lights up. Just make sure you don't touch the bulb glass since oils can make it prematurely fail and that thing gets HOT fast.

 

Ooh, that's good to know. Would a battery charger count as a 12 volt source? Or maybe jumpers direct from the battery?

 

If your battery charger has a setting for 12v power supply, then that would work. You could also connect it to the battery assuming it has a good charge.

A while back, I converted a PC power supply to use as a dedicated DC power source, if you want to go down that route.

 

I ordered another use ballast/igniter set on Ebay. This set works and now both headlights also work! Thank for your help along the way.

 

Nice! Glad you got it sorted. Now go get some fender liners to prevent issues in the future! (if you haven't already, lol)

 

Had no fender liners before.. drove through rain, hit a big puddle and lost both my headlights at 11pm..

The issue was water got into the headlight connectors..

 

Glad to see you got it sorted!

Fender liners are cheap, you can get a set of aftermarket ones on amazon for less than $60 with hardware! (Note: Only for the front half that covers the backs of the headlamps, the rear half is sold separate).

I do like the OEM pop-rivets though, Nissan updated them maybe a year or two ago. The new design seems to be more durable. I'm specifically talking about the most common size, used for liners, cowling pieces under the hood, and various body parts (like rocker covers).
Cheers!
-Icer

 

I've got the part numbers for the fender liners but haven't ordered yet. The problem is the PO (my son) put tires and wheels on that are too big up front. That's why the liners are missing. I gave him 3k for a down payment on a 370, and I got this car. I've been fixing nits in anticipation of sale.

 

If the aftermarket wheel/tire setup is rubbing the fender liners, depending on how bad it is or where they rub, you may be able to slightly modify the finder liner shape with a heat gun. I can't tell for sure, but based on your picture, that looks like a fairly aggressive fitment with some low offset wheels.

 

I think I'll order one liner and try that.