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Discussion Starter #1 (Edited)
Recently, I started getting "Check Licence plate light" warning and after verifying the bulb was good I checked the voltage at the plug and sure enough, it was not putting out any voltage. Thanks to this forum I found out that the problem was caused by a broken trunk lid harness wire(s).

After reviewing other DIYs on how to fix the broken wires I decided to go a slightly different route that did not involve removing parts. I thought I would share how I did it. The cherry on top was that I was able to fix my trunk lid unlocking switch which has never worked since I bought the car. :banana:

The insulation was cracked in multiple places, not just close to each other but as far as 6" away.


I pushed in the wire loom into the trunk and clamped the wires so I could have space to do the repair.


Next, I cut ~6" of each wire. Not all of the wires had cracks in them but I decided to cut them anyway so I don't have to come back and do the job twice.


Now comes the hardest part, soldering in new wires (~6 in). I used 22 and 18 awg wires.


I picked up this little guy to do the soldering and it worked fine. I like that it doesn't have a cord to get in the way but the downside is you have to refill it quite often. NOTE: there are 2 Grey/Brown wires, keep track of them.


Done.


Wrapped it all with low friction tape. I sprayed some white lithium grease inside the loom and the wires to help push them up and also keep them from drying out. I also kept the solder joints away from the flex area.


Like it never happened.
 

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Sanitary repair!
 

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Under the lift arms
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I think im in for that soon..

I get a random plate warning.. even thought i have no error Leds (they could be bad)

and im having a problem with my 3rd brake light now
 

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I think I may have a similar problem with the wiring. My boot door would be open randomly when I unlock the car. I'd have to get out and close it down. Anyone else have this happen?

Sent from my SM-A520F using Bimmerfest mobile app
 

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I think I may have a similar problem with the wiring. My boot door would be open randomly when I unlock the car. I'd have to get out and close it down. Anyone else have this happen?

Sent from my SM-A520F using Bimmerfest mobile app
Sounds like you are having a trunk (boot) lock actuator issue. These have been problematic since the E39s were new. I would read up but you may just need a new actuator.
 

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'17 X1 - Rooster Cruisin'
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EEK! That's a lot of solder for that repair. May I offer some constructive criticism? Whenever splicing smaller gauge wiring, join the wires with a "ol' skool" Western Union splice and allow the solder to flow within this joint by applying the proper amount of heat for a long enough time. Also use some Marine grade, heat shrink tubing that comes with a sealant/adhesive already applied inside for a compact yet waterproof splice. There are also Butt Connectors that come with the heat shrink tubing applied already - just crimp and heat to seal.
 

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I think I may have a similar problem with the wiring. My boot door would be open randomly when I unlock the car. I'd have to get out and close it down. Anyone else have this happen?

Sent from my SM-A520F using Bimmerfest mobile app
I had the same issue as you. I'd start the car, put it into Drive & I'd get the "Trunk Open" message (not always, but often enough). I'd have to get out of the car to shut the trunk.

Ended up being wires chafed just like the OP showed.
Mine was just a wire issue, no problem with the actuator itself.
 

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Mine when you press the release button under the dash, wont pop the trunk... I can hear a faint electrical click, but it doesn't open it. Same when I try using the handle on the trunk itself. I can hear some kind of electrical sound but it wont open. I always have to use the key. :dunno:
 

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Trunk Lock Question...

Update on the trunk not popping open. I replaced the solenoid today at lunch time and that did the trick. :rofl:
In your troubleshooting, did you ever locate a good wiring diagram that showed who to check out the VDO solenoid for correct operation?

My trunk light came on at the same time the key fob and manual button stopped working, so I'm inclined to think this is the solenoid...

Doug (German spec '97, 520i)
 

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I'd add one more suggestion: put something like a paper towel/cardboard, maybe even a thin piece of wood like 1/4" plywood, under the joint you're working on to prevent drips of solder from getting on things like the trunk lid jamb area, the rear glass, etc.
 

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I can't seem to find a link that discusses this but is there a way to unplug the wiring harness for the trunk lid? I picked up a deck lid recently to replace my original that developed rust below the roundel. I'd love to be able to unplug the old lid and plug in the new.
Thanks in advance.
 

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I can't seem to find a link that discusses this but is there a way to unplug the wiring harness for the trunk lid? I picked up a deck lid recently to replace my original that developed rust below the roundel. I'd love to be able to unplug the old lid and plug in the new.
Thanks in advance.
I'm almost certain not. I did the R&R for the entire harness due to one broken and several cracked, almost broken wires. I couldn't find a plug as you're hoping to find. I've never seen any reference to a plug either. I cut and reconnected with soldered joints inside the trunk, which is a bit of a contortionists job.
 
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