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-   -   Trunk release button above license plate not working (http://www.bimmerfest.com/forums/showthread.php?t=691195)

speedemn 04-21-2013 01:30 PM

Trunk release button above license plate not working
 
I have searched countless threads and have not found a solve for this outside of one potential cause which I do not believe is the case in my situation...

I am able to open my trunk lid with the button on the remote and with the button inside the car. However the button above the license plate does not work at all... no response at all.

One of the causes that was discussed in many threads here is the wires getting frayed from the trunk to the inside of the car however in my case the wires are tightly taped together and concealed within the black flexible rubber so I do not believe that I would have a frayed or cut wire in there.

What else could it be?

edjack 04-21-2013 01:33 PM

The rubber boot that seals the opening (where your fingers go) gets flaccid over time and prevents the microswitch from closing.

Just replace it.

speedemn 04-21-2013 01:54 PM

Quote:

Originally Posted by edjack (Post 7534029)
The rubber boot that seals the opening (where your fingers go) gets flaccid over time and prevents the microswitch from closing.

Just replace it.

When I depress the switch I can hear the clicking in the switch itself quite clearly... if that rubber diaphragm was flaccid it wouldn't make a solid enough connection with the spring behind it ... seems tight to the switch/spring.

Am I understanding it correctly?

speedemn 04-21-2013 03:10 PM

I took the switch itself off and there does not appear to be any visible signs of frayed wiring... all seems to be connected. Could the switch itself be faulty? Is there a way to test it independently?

edjack 04-21-2013 03:29 PM

That, and a failed actuator, are the only experiences I've had with the trunk latch.

Put an ohmmeter across the cable connections to see if the switch works.

speedemn 04-21-2013 05:54 PM

Quote:

Originally Posted by edjack (Post 7534220)
That, and a failed actuator, are the only experiences I've had with the trunk latch.

Put an ohmmeter across the cable connections to see if the switch works.

To clarify, I would unplug the trunk switch and then test the cable harness end for voltage? If I get a voltage reading then the switch is at fault... but if I do not get a reading then its something past on the wiring end?

JUBMW 04-21-2013 08:30 PM

Make sure your doors are all unlock and just push (not hold) that button and see what happens. For that button release to work you have to make sure all doors are unlock and not just the drivers door.

JUBMW 04-21-2013 08:32 PM

Quote:

Originally Posted by speedemn (Post 7534072)
When I depress the switch I can hear the clicking in the switch itself quite clearly... if that rubber diaphragm was flaccid it wouldn't make a solid enough connection with the spring behind it ... seems tight to the switch/spring.

Am I understanding it correctly?

Never mind what I said :banghead:

edjack 04-21-2013 09:39 PM

No. Disconnect the cable between the switch and the body harness. Then use an ohmmeter to check for continuity.

mbell666 04-22-2013 12:38 PM

I thought mine was faulty but then released it was me that was "broken"...

If you have your remote key set for two presses to unlock all doors, the trunk will only be unlocked on the second press of the key with all the the rest of the doors. So unless you unlock the car fully (two presses) the trunk will not open from the trunk switch/button but will from the key or internal release.

Your probably well aware of this and I don't mean to insult your intelligence but wanted to make certain you aware of this before starting to poke and prod the car with a multi-meter.

speedemn 04-28-2013 10:44 AM

Quote:

Originally Posted by mbell666 (Post 7536116)
I thought mine was faulty but then released it was me that was "broken"...

If you have your remote key set for two presses to unlock all doors, the trunk will only be unlocked on the second press of the key with all the the rest of the doors. So unless you unlock the car fully (two presses) the trunk will not open from the trunk switch/button but will from the key or internal release.

Your probably well aware of this and I don't mean to insult your intelligence but wanted to make certain you aware of this before starting to poke and prod the car with a multi-meter.

No worries... yes I got that... :)

I believe it is the switch... didn't have a chance to check with an ohmmeter yet but will be going to the dealer for another issue and they will look at this while its in there...

I will report back on what the root cause was!

bluebee 04-28-2013 10:17 PM

Quote:

Originally Posted by speedemn (Post 7549163)
I will report back on what the root cause was!

While you're there, please snap a photo of your trunk wiring loom and post to this thread:
- How to diagnose & repair cracked, broken, or frayed BMW trunk loom wires causing all sorts of strange mischief (1)

speedemn 07-08-2013 07:57 PM

Quote:

Originally Posted by bluebee (Post 7550222)
While you're there, please snap a photo of your trunk wiring loom and post to this thread:
- How to diagnose & repair cracked, broken, or frayed BMW trunk loom wires causing all sorts of strange mischief (1)

The wiring loom is tightly packed and completely concealed by the black rubber sheath. I would have to nearly rip it open to get a good shot.

After some intensive root cause analysis the conclusion is that the fault is SOMEWHERE along the wiring path but any further troubleshooting involves exposing all the wiring and taking panels and parts off... not even sure if I Should attempt this or where to start if I do! :(

rrtec 07-08-2013 08:38 PM

Same issue... I am wanting to fix it.. too much other stuff first..


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