So I've seen a couple of posts about headlight problems. I've just encountered my own, and can't figure out what the problem is.

I have a 2004 Mazda 3s (hatchback) and the passenger side low beam headlight just went out. The high beam and blinker still work just fine. I took the bulb out, and it was in fact blown. So i picked up a new one at the local auto parts for $97. I thought it was outrageous that it did not work for such an expensive bulb.

I did not touch the HID bulb and was sure to be gentle and careful when replacing it. I was worried the bulb was the problem, so i switched the bulbs from passenger to driver side and driver to passenger. Same problem. Driver's side works but passenger side doesn't.

I checked all the fuses under the hood and they are all fine.

Has anybody figured this problem out yet? I can't imagine it being the headlight assembly itself not working. I just replaced the head gasket and timing chain, but that couldn't have messed with the headlight. could it?

Any help would be appreciated. Thanks!

 

UPDATE: i tried dialectic grease and ran a volt test to see if power was getting to the bulb. I compared these results with the driver side headlight that does work. The voltage getting to the passenger side headlight is a fraction of the "normal" voltage the driver's side headlight (the working one) is getting.

I took off the ballast on the bottom of the headlight (the metal box) and it appears water has gotten through the seal. I ordered another one and should be delivered tomorrow. I'll update once i replace it to let you guys know if it works.

 

Yup. Whenever a HID lamp goes out swap the lamps first to see if the issue is the lamp or the ballast.