Remote access now unreliable - How too guide?

[Brian James]

Hi,
The remote access via my key fob is becoming unreliable in so much as it cannot always be guaranteed to lock/unlock the car - 1999 Z3 post facelift.
I have checked the fob(see photo) batteries and whilst the voltage was slightly lower than new batteries, I replaced them for good measure.
The problem still exists and is getting worse.
The car can be locked/unlocked using the key in the drivers door so I am assuming the locking mechanism is OK and the issue lies with the module ( i.e relay) in the pcb in the key remote sensor located in the (rear view) mirror.

Has anyone experienced similar problems but also can anyone point in me in the right direction in terms of dismantling the rear view mirror so as to access the pcb and get it repaired?
As always, any advice greatly appreciated - thanks in advance for your help.

 

[t-tony]

Do you have a spare key Brendan, and is it the same? I think I'm correct in saying that type of key "charges" in use.

Tony.

 

[DrWong]

Have you checked the boot loom for breaks? I have the same fob and could only unlock doors manually with my key when I first got the car - even the central locking wasn't working. Found lots of broken boot loom wires, fixed them, everything returned to normal, i.e. fob locks/unlocks all doors and boot remotely.

 

[NZ00Z3]

The relay for the central locking is not in the mirror. It's located in the General module (ZKE).

Follow @DrWong suggestion first as the loom of doom is often the cause of strange central locking problems.

 

[Brian James]

Many thanks for all your suggestions - @t-tony the spare key is the same and I changed it's battery at the same time but the problem exists with either key. Normally we use both keys on a regular basis just to ensure that everything stays "hunky dory"

I haven't removed the battery recently but will do so and check the loom carefully for breaks. Will let you know how I get on.
Not sure where the general module is located - I would appreciate any advice on this.

Thanks once again for all your help.

 

[hard top]

Not sure where the general module is located

As far as I can remember, it's behind the glove box.

 

[Ahlah69]

There’s also a drivers door switch that wears out… hold remote button and push gently in on drivers door… worn switch says door is open and no central locking .. good luck