A deer hit my 2010 TL last year and I had to replace my Driver side head light assembly. I bought a cheap ebay ballast to replace my original that was damaged. Once energized, the Driver side low beam headlight still did not work and the Passenger side low beam headlight flickered for a moment then went dark. I now have no low beam headlights. My high beam headlights work but only on certain headlight control settings. Such as, the high beam headlights will not come on with the headlight controls in the 'Auto' setting. The high beam headlights will come on with the headlight control in the 'on' position.

My next thought is to replace everything with OEM parts, but man that's a was of cash.

Has anyone seen this before and found a solution other than reverting to OEM parts?

 

What's weird is that the driver's and passenger side HID low beam and high beam are on two completely different circuits in two different fuse boxes in the cabin, but the larger fuses that control those smaller fuses are located under the hood.

In the under-hood fuse box, 30A fuse 3-6 and 3-8 protect the HID low beam, high beam, parking light, and fog light on the driver's side and passenger's side respectively. Do your parking lights and fog lights work? Not sure why the high beams would still work, but looking at the diagram, it looks like power may come from a different source when the combination switch is turned to ON rather than AUTO? (shrug)

Basically I'm wondering if that eBay ballast helped fry parts of that fuse block somehow. Check those fuses first, see if anything is blown.

 

Thanks for the helpful response. I will check those fuses over my lunch break and post what I find.

I have a couple more questions and first one may have you slapping your forehead. I looked, but apparently not hard enough, for any fuse boxes under the dash on both sides when this issue first occurred and did not see anything that looked like fuses or a panel that led to fuses. Where are the under dash fuse boxes? Second question is about the ballast...is there a suitable aftermarket ballast to use or should I stick to OEM ballasts?

Oh, and I guess one more. Do you think the cheap ballast I installed on the driver side somehow damaged to the existing OEM ballast on the passenger side?

 

Passenger side, there's a little door you slide out of the way to get to the passenger fuse box. Driver's side, peel off the plastic cover on the left side and the fuse box is deep underneath on the left side (I didn't feel like climbing underneath, and ignore the dirty floor lol). Under-hood fuse box is just behind the air intake hose, next to the driver's strut mount. See pics below.

Honestly, i'm also running a cheap aftermarket ballast lol. I did a projector retrofit a few months ago on brand new headlights, and the bolts were so rusted on my OG headlamps that I couldn't get one of the ballasts off. So I just swapped in the cheap ballast that I bought for bench testing purposes, and it's been running fine since Feb. I don't think the aftermarket ballast would've destroyed the OEM ballast considering how disconnected they are on two different circuits. That'd be the point of the multiple fuses between them, so that'd be odd if that were the case...

 

Thanks for your informative responses.

I checked the fuses of the two fuse boxes inside the car on the passenger side and driver side. I got into the one under the hood but did not get access to the 3-8 and 3-6 fuses because of the cover over them. Looking at your first response it appears there is a screw that needs removed to remove the cover. I'll try that. Probably be Friday before I can get to it though. I noticed the days are already getting shorter and I hope to have this figured out before I need to drive in the dark for work.

I also have an '03 TL that I wrecked years ago. That wreck left me without a car and is why I have the '10 TL. My plan at that time was to fix the '03 for commuter use and use the '10 for around town and long-distance trips. My daughter ended up driving the '03 through high school and undergrad, though, so that plan did not pan out well. Anyways, when I fixed the '03 I went with cheap ballasts and those lights have functioned fine for many years now so I was/am surprised when these problems occurred with the '10 TL.

 

I finally go back to this. Both ballasts are now 'genuine' Honda part numbers. New bulbs from O'Reilly's. Fuses under the hood are good. The fuses inside the car were good when last checked in July. I will recheck these.

The passenger Low Beam works. Both High Beams work. Driver side Low Beam does not work. The Driving lights work. The marker lights work. The blinkers work. All lights, front and rear, function as expected except the Low Beam Driver side headlight.

Assuming the fuses inside the car are still good why would the Driver side Low Beam still not work?

 

even if the fuse looks good, replace it. Also check the resistance of the wire from the fusebox to the ballast harness end, make sure that it's not high or showing an open circuit.

 

Good call on ohming the wires. I hadn't considered doing that yet, although my thoughts have been leaning in that direction. With all new parts there must be a break in continuity somewhere. The fuses are electrically good. That is, my Fluke reads zero ohms when applied to the fuse leads.

 

are you getting any voltage at the wires going to the ballast? It could also be a bad ground if your power is good.