Front Doors and Sunroof not unlocking/opening
 

Hello All, I have a problem, intermitent failure of the front doors and sun roof only to unlock, usually fixed by geting into the car from the back, starting and then pressing the central locking button between the two seats, always intermitent and always both front doors and sunroof. Have replaced the GM module with latest unit (car is 2000 model)this seemed to fix it and even the steering wheel adjusted itself perfectly every time which was another intermitent but livable with problem, however two days later, same problem. Ideas anyone Cheers

Something in the CAN bus shorting out perhaps...... I also had issues with mine, I had an aftermarket alarm system take down and eventually fry my body control module (one of multiple reasons I HATE aftermarket systems). Don't know if you have one, but if so that might be a good place to start

Thanks for the heads up, have not looked at that, do not have any aftermarket alarms etc. Have read that a 3 series owner hadsame problem and was issues with pins on a connector in the door itself, either corrision or wires breaking with age. Have been swapping components out with another car the same but no luck to date. Other ideas have been bad ground connection or intermitent power failure, relay? Will keep trying, has happened 3 times over 400k of driving at seeming completely random times.

Bad grounds or relays are very possible too. Cleaning all the ground points often solves many problems at once, and it's good maintenance. If you have known good parts to swap in and test, that may work out for you as well.