E90 trunk won't open electronically

Hi guys,



New to the forum. The issue I’m trying to troubleshoot is that the trunk will not open with any electronics (’08 328xi). Luckily, it can still be opened manually with the key. Here’s what I’ve been able to uncover thus far:

• The valet switch is in the unlocked position and has been toggled to make sure a proper connection is made.


• The connector going into the trunk actuator only sees 7.8 volts when any of the electronic buttons are activated (fob, button below the dash, or the button inside the trunk handle). I was told this actuator needs 12 volts to function.


• The button below the dash is seeing a constant 8.3 volts.


• The wires within the harness going from the trunk lid into the cabin below the rear window appear to be intact (the normal fatigue point from what I’ve read).


• Have not checked all the fuses myself, but dealer stated there were no blown fuses (story below).

Is there another wire fatigue point or a quick relay / connection to check? Any thoughts before I start tracing the wires would be greatly appreciated.





Here’s the story (that I feel started this whole issue):

A couple months back I sheared a motor mount bolt, and either the bolt or the mount itself dropped and cut some wires that short circuited the car. The dealer repaired the mount and wires; however, after picking up the car, the trunk couldn’t be opened electronically. I find it a bit too coincidental that wires were cut/fixed and now I’m having an electrical issue. The dealer stands by not touching any of those wires/connections. I don’t know enough about where all the wiring is to agree with or refute their viewpoint.

E90 trunk won't open electronically