Hi all,

Looks like I'm experiencing the trunk release problem. The weird thing is, I am 99% sure the switch is OK, but I don't know how to debug the wiring. I got my hands on the wire diagram for the trunk release. Basically:

- if I measure voltage across pins 1 and 3 on the left side (switch), I get 12V
- if I connect the whole switch assembly (lights etc) then lights work, but pressing the button does not work (however, if I measure voltage across the switch's pins, I can see the button is working)
- if I short pin 1+3, the lock does NOT disengage.
- remote works fine



How do I figure out where my problem is? I am tempted to go to the junction box A4010, it seems pin 24 on the junction box == pin 1 on the left side diagram above, but I don't know what this would tell me, since I _do_ have 12V on that pin, so clearly it's getting power.

Any advice on what I can look for?

 

The little button gets wet underneath and corrodes the connection after the rubber damn gives it up. You can order the button assembly, which is attached to the trim piece from Pelican Parts. Not too expensive and pretty easy install.

This is the name of the part

 

I should have said our other option is to pull the part off the car and unsolder the old button and install anew one. The only problem is it doesn't keep the weather from getting to the electronics. Also, try and find a small enough push button to solder in. Brother, your chasing rabbits trying to pinch pennies on this fix. And, the ghost is spending all that time pulling the trim piece and opening it up to unsolder and locate another push, then it doesn't go away cause the weather will get to it. Plus, have you ever unsoldered and solder electronics? That's why BMW put the little rubber dam over it, keep the elements out. BTW, I chased that rabbit for one day.

 

Thanks for the reply. Apologies that my message wasn’t clear. The problem isn’t with the button, I think - and I’m not trying to desolder it (some other DIYs talked about it, but that isn’t my problem). My problem seems to be that the button doesn’t unlock anything - and I have two grip handles here that I’m trying, and somehow I am doubting that BOTH are defective. Also, since I’m attempting to short pin 1 and 3 of the wiring harness with a paper clip and it’s not triggering the trunk release leads me to suspect that the switch isn’t my problem - but I don’t know what is.

So what I’m trying to figure out first is, if it isn’t my switch - then _what_ is the problem and how do I trace it?

 

Update - I got my hands on a _third_ trunk grip, and the button release does not work, period. Remote works fine.

So now I’ve tried a) shorting pin 1 and 3, and b) _three_ different trunk grips.

How do I debug this? Where’s my problem?…

 

Jesus Christ, I am so dumb it almost makes me cry.

Even though the locks were up, I didn't press the "unlock" button when I was trying it. So for whatever reason, the car still thought it was "locked", hence it was ignoring the trunk switch.

So obviously once I did that, everything started working fine. Now I can reassemble the damn thing.

False alarm... apologies everyone. Make sure to unlock your locks before you panic!!! (my work wasn't wasted - the trunk grip _was_ bad, and I was installing a rearview camera anyway, so it's all good).