Range Rovers Forum banner

Open heart (BeCM) surgery.

8400 Views 8 Replies 6 Participants Last post by  tomcatrr
Today im going to remove and open up my BeCM to hopefully get the sunroof working. it packed up ages ago, stuttered when half open and stopped, hasn't worked since, i have swapped out everything and checked continuity from all the wires from motor to BeCM and switch pack and BeCM, i had the sunroof disabled in the BeCM and got full closure and double locking working just fin e so i know its just the sunroof not being set thats stopping this from working, so today its out with the BeCM and stripping it down to change a defective relay soldered onto the power board.

I got a spare BeCM so plenty of spares are available, il be doing this at a friends house who is a wiz with this sort of thing just for moral support really, il no doubt take some picks and post them up later.

Wish me luck PLEASEEEEEEeeeee..................lol
1 - 9 of 9 Posts
Good luck, looking forward to the pics and hearing the result.
Good Luck mate :thumb:

I presume you swapped out the window switch control pack?
Are you sure it's a relay and not a failed chip on the logic board?


IT WORKS got sunroof working and full auto closure of windows and sunroof when double locked first time in nearly 4 years!

full write up to follow as i think its a fault taht will be quite common to other BeCMs...just gonna have me dinner
Congrads. This is killer terrific news!
I can't believe you did it.

Well done Mark, i'm impressed. I thought you'd never get round to it. The becm i gave you wasn't wasted after all, or did you use the single relay i gave you?
I did have a little help, lol and it wasn't a relay fault! the PCB had a faulty "Through plate" on it. this is a small copper tube inserted into the PCB where a track changes from one side of the board to the other, it wasn't conducting power so the control chip for the relay (output from pin 14) wasn't able to get to the relay coil, so we soldered on a bypass wire and hey presto...

look at below pics for brief description...

Seat removed and cover off of BeCM showing the sunroof relay

this is the spare BeCM (thanks again Rick) that we removed the relay from to see whats going on under it, follow the white line from A to C this is the track feeding the relay coil from the "Through plate" its supplied from under neath from the ic chip leg 14 shown here as "B"

We found details of the relays pin outs here http://www.bmwgm5.com/GM5_FW_Relays.htm this also made working out the schematics a lot easier as well

this is the under side of the BeCM PCB and again the white line shows the start and end points of the track from ic chip leg 14 (B) to the "Through plate" "A"

So we soldered a wire from C (relay) to B (ic leg 14) bypassing A (Through plate) completely. the strange thing is the old BeCM i was given (thanx again Rick) had exactly the same fault as mine did, the "Through plate" being unable to conduct electricity.........so maybe this is common cause of sunroof failure, maybe???

anyhow i have to offer a huge thank you to my mate Stuey, http://www.supradupra.com as without his help i probably would have been a little stumped, and yes just a little, lol, thanks Stuey.
See less See more
Good work and thanks for share it :thumb:
1 - 9 of 9 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.