Central locking problem

[Liquid790]

HI.
Just wondering if anyone can shed some light on my central locking problem.

First of all I performed the red/black wire mod many years ago, so don't believe that's the problem.

Basically using the key in the boot operates the central locking normally.
The driver's/passenger door and the remote fob will only lock all the doors.

I have checked all the obvious wires in the passenger footwear for solder breaks e.t.c

Any ideas would be very much appreciated

Dan.

[Brianmoooore]

The boot look has separate lock and unlock request wires to different pins of the ECU from the wires from other locks, and the ones the remote locking i usually connected to. http://www.autolib.diakom.ru/CAR/BMW/19 ... /fig10.pdf The wire that is not working is the green/blue.
Lock the car with the passenger door open (it will automatically unlock again if the driver's door isn't shut), connect one end of a piece of wire to a good body earth, then use the other end of the wire to earth the green/blue right at the ECU.

[Liquid790]

Cheers Brian.

I earthed the thick green blue wire at the Ecu and it didn't seem to make any difference.
My remote locking seems to now be struggling to lock the car as well.

This wouldn't be a problem but my drivers door lock is fairly worn so I try not to use it.

Dan.

[Brianmoooore]

Looks like the locking ECU may be faulty, but to be sure , you'd have to disconnect all four lock and unlock request wires, plus the deadlock wire, from the locking ECU, leaving the two power wires and the three wires to the lock motor still connected, and then try earthing all four request pins in turn. Two should set the locks, and two should unlock them.
Try removing the locking ECU, opening it up, and see if there's any visible clues inside.
Cleaning off 30 year old grease nd relubricating the lock/catch linkage in the doors can transform the performance of the locks.

P.S. I can think of no reason why BMW chose to have separate inputs on the ECU for the boot lock from the other locks, and therefore no reason why they can't be combined to the working pin if the ECU is faulty and unrepairable.

[Satan]

P.S. I can think of no reason why BMW chose to have separate inputs on the ECU for the boot lock from the other locks, and therefore no reason why they can't be combined to the working pin if the ECU is faulty and unrepairable.

Am I correct in thinking that the boot can be deadlocked independently from the doors?

[Brianmoooore]

P.S. I can think of no reason why BMW chose to have separate inputs on the ECU for the boot lock from the other locks, and therefore no reason why they can't be combined to the working pin if the ECU is faulty and unrepairable.

Am I correct in thinking that the boot can be deadlocked independently from the doors?

It can be, but it's a mechanical deadlock - it moves a bit of the linkage out of the way. There's no deadlock motor in the boot actuator.

[Liquid790]

Thanks.
I shall fish the locking Ecu out and.have a look at it

Dan.

[Satan]

P.S. I can think of no reason why BMW chose to have separate inputs on the ECU for the boot lock from the other locks, and therefore no reason why they can't be combined to the working pin if the ECU is faulty and unrepairable.

Am I correct in thinking that the boot can be deadlocked independently from the doors?

It can be, but it's a mechanical deadlock - it moves a bit of the linkage out of the way. There's no deadlock motor in the boot actuator.

Like the drivers door when you turn the key a tad extra?

[Brianmoooore]

Essentially, yes, although there's no 'over centre' mechanism that snaps over. The only electrically operated deadlocks are on the front passenger door and the rear doors.

[Liquid790]

So to cut a long story short.
The central locking Ecu looked fine so I ended up wiring my remote locking into the boot request wires.

All works fine now

Dan.

[Brianmoooore]

Looks like the ECU is faulty, but it's a specific fault I've never come across before.

[Liquid790]

I have the.interior light delay relay plugged in next to it but in 16 years I've never had the.delay function.

Do you.think a new relay will sort this?

[Brianmoooore]

I'd check the operation and wiring of the door handle switch first.

[Liquid790]

Cheers Brian.