cavalier central locking

[Debngrae]

hi all am having an issue with the central locking on the old cavalier ( M REG 1800 ) when I lock the car using the key in the drivers door all doors and the boot lock but then straight away the other three doors and the boot open again
any help would be great
many thanks

[Robsey]

I have this issue if the front passenger door is not locked.

If I drop the passenger side plunger, then all doors remain locked.

If this does not work, try doing the same with the boot lock.

That is - turn the lock in the boot to the vertical (locked) position, then retry the driver's door lock again.

Unlock, then lock.

The reason for this is that both the front doors and the boot / hatch locking mechanisms are able to operate the lock and unlock functions of the central locking module.
If the driver's door is not in the dead-lock setting,
And the boot / hatch is not in the vertical ignore central locking module position.

Possible causes are-
1 - displaced / faulty / mal-adjusted micro-switches, link rod or door solenoid in the driver's door.
2 - faulty / mal-adjusted link rod or door solenoid in the front passenger door.
3 - faulty / mal-adjusted link rood or boot solenoid or the wiring is damaged in the hatch where it flexes inside the rubber boot near the nearside hatch hinge.

If it has never failed before, try removing fuse 17 for a minute or so, then refit it again.
I think fuse 12 is also used, but be sure that you have your radio security code (original car radio) before you pull this out and refit it.
I cannot remember if it is fuse 8 or 12 that controls the radio's permanent live.

This should reset the central locking module.

[Debngrae]

ok thank you will try it tomorrow and let you know the outcome
many thanks

[cavalier1990]

Very common for the wiring loom for boot lock to split just at the back of the boot hinge arm. Open boot and look at wiring as it jumps from hinge to upper part of inner wheel well. This can cause the locks to short and play funny beggars.

[Robsey]

As an update to this - and in response to Andrew's comment...

Flexing of the loom inside the rubber boot between the tailgate and the car roof can also cause central locking mayhem.

I had many wires that were snapped and shorting out in my hatch in the summer.
This caused all sorts of random unlocking of the central locking and in my case triggering of the 3rd party alarm.



Repairing all the damaged wires going to the hatch has cured my intermittent problems.