[eshroom]

I had a very minor front end accident in the summer, insurance assessed it as minor cosmetic so I didn't bother claiming.

I drove to the airport before Xmas, a few hours drive in really heavy rain. Parked up for two weeks, came back yesterday and my N/S xenon was out with a load of condensation in the headlight. Started driving and both actuator warnings (left right, up down) came on.

I thought the water may have burned a fuse so I checked headlight fuses, but there are no issues there. Does anyone have any ideas?

I imagine the bump i had allowed some water under the bonnet on the N/S, which subsequently made it in through the top headlight to cover, which has no gasket presumably as it is normally always dry there.

[nsjames]

water in the headlamp usually kills the AHL module.
when a module fails the car disables the entire AHL system.

so sadly you're probably into it for a headlight.
usually they get water in them because the cover on the back isn't secured. perhaps it popped off in your accident.

[eshroom]

Thanks. Is that also known as the ballast module? If so, I can get just the module fairly inexpensively, just a PIA to change.

The back cover seems fully in place, but there is a lot of condensation in the headlights, clearly, a fair amount of water got in.

[nsjames]

no, the balast is what powers the headlamp.
the AHL module is tucked on the bottom of the lamp. You'll have to remove the headlamp from the car to get at it.

because it's in the bottom it's the one that gets damaged when water gets in it.

You may want to try pulling the headlamp and drying out that module/cleaning it's connector.
maybe you get lucky and the module hasn't been damaged from long term corrosion, and it's just mad because there's water in the connector shorting something.
replacing the AHL module will require coding IIRC.

Pelican has a good DIY to remove the headlamps.

[eshroom]

Originally Posted by nsjames

no, the balast is what powers the headlamp.
the AHL module is tucked on the bottom of the lamp. You'll have to remove the headlamp from the car to get at it.

because it's in the bottom it's the one that gets damaged when water gets in it.

You may want to try pulling the headlamp and drying out that module/cleaning it's connector.
maybe you get lucky and the module hasn't been damaged from long term corrosion, and it's just mad because there's water in the connector shorting something.
replacing the AHL module will require coding IIRC.

Pelican has a good DIY to remove the headlamps.

OK, thanks, I'll get to work on the headlight asap then.

[TheMidnightNarwhal]

Originally Posted by nsjames

water in the headlamp usually kills the AHL module.
when a module fails the car disables the entire AHL system.

so sadly you're probably into it for a headlight.
usually they get water in them because the cover on the back isn't secured. perhaps it popped off in your accident.

Why buy a whole new headlight when you can just get a new module if his module is the issue.

[eshroom]

Follow up question: You mentioned AHL module failure would cause Xenon headlight to not function. Would ballast case AHL to also not function? I.e. could either one (or both) be the problem, and which one would you say is best to try first?

[nsjames]

Originally Posted by TheMidnightNarwhal

Why buy a whole new headlight when you can just get a new module if his module is the issue.

because he can probably buy a complete used working headlamp replacement for what a module costs, and he's not sure if his is cracked or damaged letting water in. They should be 100% sealed if the back cover is on correctly.

I replaced my headlamp with a good used one for $150.

I swapped my AHL onto it because my old had broken mechanicals inside, but the seller told me it was fully functioning until the car was wrecked and parted.

[nsjames]

Originally Posted by eshroom

Follow up question: You mentioned AHL module failure would cause Xenon headlight to not function. Would ballast case AHL to also not function? I.e. could either one (or both) be the problem, and which one would you say is best to try first?

I don't think so.
but maybe.

I had a headlamp fail and the AHL kept right on working on the other side.
I just got the bulb error.

regardless if you have water in the lamp, it has to be pulled. It's known to kill AHL modules.

[TheMidnightNarwhal]

Originally Posted by nsjames

because he can probably buy a complete used working headlamp replacement for what a module costs, and he's not sure if his is cracked or damaged letting water in. They should be 100% sealed if the back cover is on correctly.

I replaced my headlamp with a good used one for $150.

I swapped my AHL onto it because it had broken mechanicals inside, but the seller told me it was fully functioning until the car was wrecked and parted.

Guess it depends LCI or not. I don't think he is LCI so it would be cheaper.

A new headlight is about 500$ for me while a new module is 200$.

[nsjames]

Originally Posted by TheMidnightNarwhal

Guess it depends LCI or not. I don't think he is LCI so it would be cheaper.

A new headlight is about 500$ for me while a new module is 200$.

and that's cheaper than a used working complete assembly how?

like I said, I replaced my broken headlamp for $150. I still have a spare AHL and ballast from it sitting in my parts room.

a new hella replacement for my pre lci wagon is $600 shipped from rockauto.
looking at the photos I'm not even sure that includes any electronics.
edit:
some more digging in the details:

HELLA BI-XENON HEADLIGHT: 354688061
Specifications:
Genuine Hella Headlight
Fits RH (Passenger Side)
Replaces dealer part number: 63 11 7 161 670, 63117161670
Includes lens & housing
Direct replacement
Built to strict quality control standards
Does not include bulbs, ballast, or control module
Fits Sedan & Wagon models with Bi-Xenon HID (High Intensity Discharge) Headlights with Adaptive Headlights

it's a $600 housing that comes with nothing but the wiring harness and mechanicals inside.
no modules

[eshroom]

Thanks for the suggestions! It's a lot of water and sudden, so on removal I should be able to identify where it got in from.

Based on this, I will decide whether a new headlight assembly is needed.

At the same time, I'll dry everything out and hope for the best. It worked for the fan blower (well, that and a bit of wd40).

[TheMidnightNarwhal]

Originally Posted by nsjames

and that's cheaper than a used working complete assembly how?

like I said, I replaced my broken headlamp for $150. I still have a spare AHL and ballast from it sitting in my parts room.

a new hella replacement for my pre lci wagon is $600 shipped from rockauto.
looking at the photos I'm not even sure that includes any electronics.
edit:
some more digging in the details:


it's a $600 housing that comes with nothing but the wiring harness and mechanicals inside.
no modules

Well the LCI headlights are a bit cheaper overall.

Yes but in your case you are pre-lci + touring. Coupe LCI headlights are much more expensive.

My 500$ price was for a used one, not brand new. So a module is the much cheaper route in my case if the issue would be with the module.

[eshroom]

Photos of removed headlight below. Dripping with water, but not so much corrosion - consistent with the fact they suddenly filled with water during the massive storm I drove through for 4 hours.

I have left the covers as they were when I removed the headlight. Can anyone tell where the water may have got in from?

Also as a bonus, what is the part circled in red? Access for the indicator?

[nsjames]

no idea how to find the leak.

maybe some light air pressure on the inside and some soapy water on the outside?

it's got to be cracked or separated somehow to allow that much water in.

[TheMidnightNarwhal]

So basically water can infiltrate by any one of those covers and modules + the lens itself.

I think as nsjames say soapy water and air pressure would be best bet. I would start with lens and covers then go to the modules.

[eshroom]

So i couldn't pressure test but I tested with water and found a crack. Weird thing is it is in the corner at the lowest point at the front and it's tiny. Strange to think all that water got in that way.

But I guess it explains why it took cataclysmic weather before water did get it.

Thinking a super glue and silicone. Thoughts?

I've also given the ballast and other piece a vinegar/distilled water wash and scrub (seems pointless surrounding the ballast electronics with aluminium without actually trying to make them waterproof, just makes cleaning them impossible). Rinsed again with distilled water and once dry will rinse once more with isopropyl alcohol 99.9%. This process brought my coffee covered MacBook back to life, so may well work here!

[nsjames]

the process is good for cleaning the electronics.

I would not use super glue, it's pretty inflexible and it will crack.
silicone is meh.

I would sand right at that crack with some 400ish grit sand paper and then lay a small piece of fiberglass cloth over it with some epoxy.
I'd use epoxy and not polyester resin because it tends to stick to plastic better and generally just has a higher bond strength.
I'd use cloth and not mat because it's going to lay over that better and be easier to work with in such a small strip.
Probably a pretty light piece too, 3oz, maybe lighter, but I find 3oz cloth is about right for most everything.

[eshroom]

Originally Posted by nsjames

the process is good for cleaning the electronics.

I would not use super glue, it's pretty inflexible and it will crack.
silicone is meh.

I would sand right at that crack with some 400ish grit sand paper and then lay a small piece of fiberglass cloth over it with some epoxy.
I'd use epoxy and not polyester resin because it tends to stick to plastic better and generally just has a higher bond strength.
I'd use cloth and not mat because it's going to lay over that better and be easier to work with in such a small strip.
Probably a pretty light piece too, 3oz, maybe lighter, but I find 3oz cloth is about right for most everything.

That's not a bad idea. I have all that stuff at my family home in Greece, I did a bunch of fibreglassing on a small boat last year. I am going there in April. To last till then I'll use superglue and skip the silicone, then fibreglass over the top in April.

[eshroom]

So I ended up using an epoxy 2 part glue I had lying around. I think this is a good choice as it offers a bit of flex compared to superglue and as nsjames mentioned, better adhesion to the plastic. Let's see if I can get away with not carrying out further repairs.

[eshroom]

No joy. Electronics still fried. Let's see if the housing doesn't take on water. If it does, new headlight, if it doesn't new electronics. An OBD reader should tell me if it's ballast or AHL right?

[nsjames]

if it's the AHL there should be a adaptive headlamp error.
unless it's the part that drives the motors and it thinks it's working.

you can swap ballasts side to side.
I'm not sure if you can swap the AHL modules.