moretech

Interior white trunk light just stopped working. Trunk opens and closes fine. All interior lights are ok, they turn on when door opens or when remote unlocks doors. Red light in door for trunk unlocked works right. Emergency open trunk light works right. Checked bulb it is ok. No 12 v signal in wiring to connector. Circuit is grounded. Was working just fine the other day. Any thoughts on this one? Maybe my repaired soft close mechanism has failed in some other way? I see looking back at the great repair post on the mechanism there are some electrical connectors to it but I do not know what they do or if one may provide power to the light bulb when unlatched. The white wire with blueish green colored stripe appears to be the hot wire, brown wire ground, does anyone know if there is a similar connection at latch?

Moretech

moretech

Problem solved! Problem was with the bulb holding fixture. Bulb worked when powered by my 9V energizer battery when alone but NOT in the holding fixture. I twisted it around some and it would turn on on the 9v battery. Back into the trunk and light on. The fixture seems perfect and tight on the bulb. Live and learn, if it fails again I'll know where to start.

moretech

High Technology

Bumping this thread, just to share my recent experience. My trunk light stopped working a few months ago, and I never got around to fixing it. Turns out my issue was the bulb but it wasn't burnt out, Rather the metal end seems to have lost contact with the filament (the end cap spun freely and I was able to pop it off). I think it was just old age and vibration, being over 10 years old the adhesive finally failed.

The bulb in my 2009 SL550 is a 6411 (41mm festoon) bulb. My local WalMart had the Sylvania LED in stock for $6.75, so I bought that. No joy -- the bulb would only blink about every 5 seconds, likely a CANBUS compatibility issue between the LED bulb and the lighting controller. I didn't try any of the "CANBUS" compatible LEDs from Amzon/Fleabay as most came in 5-packs and I've had poor longevity experiences with many non-brand name LEDs.

My local Autozone had the incandescent Sylvania 6411LL (long life) bulbs in stock -- 2 pack was also about $7 with tax (Amazon had them for about a buck less, but not thrilled at Amazon's shipping for fragile items). Those worked fine, and it was literally a 5 minute fix. I didn't take pictures, but process is as follows:

1. Pry top of light fixture from plastic trim of the trunk (it just tilts out from the top). I used a plastic little tool designed to open electronics, but could have used a very small screwdriver (Hint: if you use a screwdriver, wrap the blade with electrical or some other thick tape to prevent scratches). Gently remove the fixture from the trunk, and you should have a few inches of slack in the wire.
2. Squeeze the release on the wiring harness to the light fixture and unplug it -- make sure the wire doesn't drop into the open space where the light was. Mine had plenty of slack and happily stayed out on it's own, so this comment is merely a precautionary thought. It's not fun trying to finesse one of these bulbs into the fixture when you only have so little slack in the wire.
3. Replace bulb in the fixture -- you might find that one of the metal contacts may flex more than the other, so that's the one you want to manipulate to get the new bulb in (start with the opposite end first, then finesse the more flexible contact). MAKE SURE THE POINTY PARTS OF THE BULB ARE INSERTED IN THE HOLES OF THE CONTACTS, so nothing slips out.
4. Plug the wiring harness back into the fixture. If the bulb doesn't light, close the trunk, lock the vehicle and then pop the trunk. If you've had the trunk open for long enough, the controller will cut the power to the trunk light. If it still doesn't work, close the trunk and go for a short ride and see if it works after that (again the controller might be doing odd things if it detected the bulb was out). If it still doesn't light up, check the other threads here related to the trunk switches (which I've not had to deal with yet).
5. Once you've confirmed it's working, reinsert the light fixture back into the plastic trim, bottom first, then tilt top end back to clip it back into place. Take 5 seconds to smile and admire your handywork.
6. (OPTIONAL) If your bulb swap went easy, this step might not be warranted, but I've always found a cold IPA (or other drink of choice) to be a good reward for fixing anything on a German car. If you ended up having difficulties and/or needed to drive to multiple stores to find the bulb, a second drink might be in order... Of course, no driving during/after the drink if your beverage of choice contains alcohol.

tallguy2020

This bulb (very bright) worked for me, its a 1W bulb with some CAN bus provisions from Amazon.ca