[SOLVED] HID Headlight (Ballast) Short?

Brado

Brado

Problem Encounterer
Greenie N00B Member
Year/Make/Model: 2008 Mazdaspeed3
Mileage: ~165K chassis / ~5K motor
Location: Arizona
Concern: Low beams shorting
DTC's: None
Modifications: Stock block, BNR S3V4, 3” intake, catless DP, 3” exhaust, etc.
ECU/Tuning Software: Cobb Accessport V3
Tuner: DramaTuned
Is the concern intermittent? All the time, officially.
Can you duplicate the concern? Yep, blew a spare fuse!
Recent Repairs: None related.
Correction: Newish build all together.

Alright bois, another month another issue! Lately after getting my car washed via touchless automatic washes, I've noticed my passenger side headlight housing get condensation on it after a bit. These headlights are old, so I'm not surprised if some moisture gets in. My headlights are getting rebuilt and retrofitted later this year, so this condensation was not a big concern for me...until I noticed my passenger side low beam wasn't working.

You can skip the paragraph below, probably.

Anywho, thinking the OEM ballasts finally shit the bed, I swapped the driver side ballast over to the passenger housing and that worked just fine if I recall. Forgive me as I swapped many things around before realizing the fuses were blown and can't remember the order. Anywho, I took what the passenger side ballast and threw it on the driver side to double check and that didn't work. Thinking I had solved it all and putting the driver side ballast back to the driver side housing, that also didn't work now. Alright, so 15 minutes later I find out that both fuses 60 and 61 in the PJB were blown. I replaced the passenger side one and tried the original passenger side ballast just to see if the ballast was ok and that blew immediately again. I'm out of fuses and couldn't keep trying, don't worry.

My question: Can a presumed broken HID ballast cause a short, or is it something within the wiring harness instead?

Mainly looking to know if I should order a new ballast or start hunting down a short within the harness. The ballasts are cheap enough and I'm likely going to order two of them anyways, but want to make sure my problem is solved definitively.
 
You washed the car and probably got moisture into the connectors causing the short. I'd remove the head lamp housings and blow all the connectors dry with shop air or dust off if you don't have access to a compressor.

If it was a bad wire you could tell by disconnecting the suspected connection at the head lamp and replace the fuse. Then turn the lights on and see if it pops when it is disconnected from the housing. If it does then that means somewhere a wire is directly shorted to ground or there is still more moisture somewhere in the harness.

If it doesn't pop then you probably have a bad ballast that is shorted internally. When you swapped the driver's side to the passenger side and back again it probably carried moisture over causing the short to appear on the driver's side which is why that fuse blew.
 
L337TurboZ said:
You washed the car and probably got moisture into the connectors causing the short. I'd remove the head lamp housings and blow all the connectors dry with shop air or dust off if you don't have access to a compressor.

If it was a bad wire you could tell by disconnecting the suspected connection at the head lamp and replace the fuse. Then turn the lights on and see if it pops when it is disconnected from the housing. If it does then that means somewhere a wire is directly shorted to ground or there is still more moisture somewhere in the harness.

If it doesn't pop then you probably have a bad ballast that is shorted internally. When you swapped the driver's side to the passenger side and back again it probably carried moisture over causing the short to appear on the driver's side which is why that fuse blew.
Click to expand...
Super helpful response! I am currently awaiting more fuses to arrive to troubleshoot further, but will try the method of leaving the lights disconnected and checking for popped fuses that way. I'm hoping it's a bad ballast itself because electrical gremlins are the last thing I want to work on.
 
Decided to just throw a 10A fuse in the PJB 60 and 61 slots respectively and see if either popped with the lights disconnected. Neither did, so I plugged the driver side light in and it worked without issues. Plugged the passenger side light in and it popped instantly. Definitely looking like the ballast has shit the bed, which is good. Two more are on the way and this should be another easy fix! Thanks @L337TurboZ!
 
Update. So I got my replacement ballasts in and installed them both, and the lights worked! Awesome, so I bolted everything back together and went for a drive, only to realize the passenger side was not working once I pulled back into the garage.

I haven't begun the disassembly process again, but I'm at a loss for what could still be the lingering issue. I can't drive at night anymore and it's kind of a bummer!
 
Update to the update. Issue resolved. Checked the fuses first and neither was blown, hooray! Turns out these replacement ballasts have slightly thicker pins than the OEM ones, so as I was driving the pin must have pushed the wire out enough to stop working. I carefully connected it back together and made sure the wires didn't back out at all and she's back to working.

For $20 a ballast, I can't complain too much. lol

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