Wiring for Trunk Light

HarryD · Post by **HarryD** » Fri Sep 14, 2018 9:37 pm

I noticed my trunk light was not working. I checked the bulb and the fuse and they are ok. I checked for voltage at the bulb base with none found.

I read that the switch for the light in in the rear trunk latch. I removed the trunk latch and found a two wire connector (with brown wires) laying loose in the area. It appears to the be the same wire on the lamp holder.

I am unable to find where this connector plugs into. There was no area on the latch mechanism for this wire to plug into.

Does anyone have a picture showing where the connector is located or can tell me where to look?

Post by **srhutch** » Fri Sep 14, 2018 10:12 pm

The two wire connector in the latch is the electronic latch release only I think.

I have a spare in the garage so should be able to take a picture for you tomorrow.

HarryD · Post by **HarryD** » Sat Sep 15, 2018 4:02 am

My electric release works just fine. There is a multi wire connector on the left side of the latch. The connector will not even reach the latch mechanism.

The one listed at ECS looks like mine: https://www.ecstuning.com/b-genuine-bmw ... 247840617/

Here is a picture of the mystery connector and the latch as installed in the car.

Jl-c · Post by **Jl-c** » Sat Sep 15, 2018 12:57 pm

Please don't be offended, but you realise that if the doors or boot (sorry trunk) are left open for a while the electronics turns them off. You haven't just noticed that it is not lit when cleaning the car and it has been open for 15 minutes or so? Just checking because I have a friend who chased similar for ages until he closed the car up, reopened and hey presto it worked!

Post by **srhutch** » Sat Sep 15, 2018 1:02 pm

Your centre brake light is working?

HarryD · Post by **HarryD** » Mon Sep 17, 2018 3:39 am

Jl-c wrote: ↑Sat Sep 15, 2018 12:57 pm Please don't be offended, but you realise that if the doors or boot (sorry trunk) are left open for a while the electronics turns them off. You haven't just noticed that it is not lit when cleaning the car and it has been open for 15 minutes or so? Just checking because I have a friend who chased similar for ages until he closed the car up, reopened and hey presto it worked!

Not a dumb question (in my world there are no dumb questions) so no offense taken.

The light does not illuminate at any time. This afternoon I had some time to do some testing with my voltmeter. With the trunk lid open, I have 12 volts on one side of light. The ground side is open. When I connect the ground side of the light to the negative terminal of the battery, the light illuminates. This is tells me that my ground is missing.

Does the servo provide power to the light or complete the ground circuit? The wiring diagram will tell the tale and then I will know where to look.

HarryD · Post by **HarryD** » Mon Sep 17, 2018 3:42 am

srhutch wrote: ↑Sat Sep 15, 2018 1:02 pm Your centre brake light is working?

Good question. Yes, it is working.

HarryD · Post by **HarryD** » Mon Sep 17, 2018 7:09 am

I was able to get a wiring diagram. I verified that the trunk release also switched the light by completing the ground circuit. It appears I have a break in my connection between the trunk release and the light. I would guess the break is at the flex joint between the trunk lid and the body.

When I have some time, I will investigate and repair.

HarryD · Post by **HarryD** » Tue Sep 18, 2018 5:14 am

It turned out to be a broken wire (brown with yellow stripe) in the flex connector between the trunk lid and the body. I spliced in a new section and all is ok.

AveZ4coop · Post by **AveZ4coop** » Tue Sep 18, 2018 6:37 am

Z4-forum.com

Z4-forum.com