Every time I think I know what the issue is, it turns out to be something else. I’ve confirmed it’s not the button on the lid, or the lock itself, the lock just not receiving a signal when it should. When I press the hatch button on the key. the lights blink twice on the vehicle but no voltage is applied to the line. There’s 4 pins, I haven’t been able to figure out what does what. I’m not sure if the cable is damaged somewhere, but I’m also not sure how to check. I can’t find any information on where it connects, or the easiest way to access that connection. I’ve checked all the fuses. I can’t find any unlock it via the mechanical release under the seats.

Any advice is welcome I’m stuck.

 

You can or can't unlock it using the pull cord under the seat? I remember on my old R50 that the hatch would sometimes get out sync for lack of a better explanation, where sometimes it would "half" lock, sometimes lock while the hatch was still up, sometimes not want to unlock electrically. I'd have to release it manually, then mess around with the lock with a screw driver to get it into the right position to be in sync with the hatch.

 

I can release it with the pull cord under the seat, it just doesn’t open electrically. I do see that there’s kind of 2 locked positions. The car can detect when it’s locked. I tried disconnecting the rear handle button and using the key, still nothing. This is a brand new lock, it’s not a dead motor.

 

Neighbor just spent three years dealing with that sort of thing on her R52, I tested the as much as I could thought it was the Body Control Module ... then it turned out to be a wiring issue.

 

Darn. From what I’ve seen, the wiring just goes to one giant connector in the BCM right?

I did do some testing with a multimeter, pins 1 and 4 are connected to ground. Not sure if that’s normal, but both their wires are the same colour. Pin 3 (might have it mixed up with 2) supplies a constant 6 volts, and pin 2 does almost nothing - although it is still connected to the BCM. How can I rule out the BCM as the issue?