Central Locking. 1990 325Cab.

[jmec]

1, Central locking didn't work but all locks worked individually on key. 2, Found control unit (mounted on plate inside drivers speaker panel) resoldered thermal switch. 3, Central locking still didn't work but still working individually on key. 4, had a little cry! 5, carried out red/black wire mod' but now doors permanently unlocked. Can't turn key, can't push buttons down. Soldered link still ok. 6, swore a lot & had a big cry! Does anyone know what's going on here? I'll settle for being able to lock the doors/boot with the key.

[Topblag]

I had a similar problem, replaced the relay and all is fine. I didn't opt for the wire mod, felt it easier to replace it.

[Rav335uk]

Sounds like the Deadlock has kicked in.
Did you solder the thermal switch with the existing solder, or did you use new?

[jmec]

Thanks for the replies.
Rav-I used new solder, not sure though if it was soft & maybe it needed to break through being overloaded? If the deadlock has kicked in, which seems likely, how do I get it out?
Topblag-when you say relay do you mean the control unit or is there a relay in the system. And when's Still Game coming back on? That'll cheer me up!

[Rav335uk]

1st mistake, is you should have just soldered with the origional solder from the relay.

The new solder has a higher melting point, so you've done more damage to the relay, and maybe burnt out the solonoids too.

[Topblag]

Thanks for the replies.
Rav-I used new solder, not sure though if it was soft & maybe it needed to break through being overloaded? If the deadlock has kicked in, which seems likely, how do I get it out?
Topblag-when you say relay do you mean the control unit or is there a relay in the system. And when's Still Game coming back on? That'll cheer me up!

The 'control unit', the black rectangular thing mounted onto the brass coloured plate which clicks each time the central locking works. I tried to solder it and it didn't work for me either - as Rav says, you need to use a specific type of solder.

Every day is a school day.

PS - the guys who made Still Game have fallen out again so it may never be back.

[Brianmoooore]

The locking ECU used on E30s is ultra reliable, and only normally fails if it's been flooded as a result of the failure to keep the sill water drain slots clear.
The thermal cut out only trips as a result of a problem elsewhere, and by re soldering with normal solder instead of the correct low melting point stuff, you have rendered it useless, leaving the whole locking system with no overload protection. The equivalent of fitting a 30A fuse in place of a 5A one.
(Fuse 27 only provides short circuit protection.)
There's no dead lock motor on the driver's door so that's not the problem there. Release the two small self tapping screws that hold the lock motor on this door in place, and see if the lock can then be operated by the key. If it now can be, check if the actuator rod on the lock motor can be moved up and down by hand. If it is locked solid, the chances are that the ECU has delivered a continuous unlock signal to all the lock motors, instead of a short pulse, and has fried the lot.

[jmec]

Many thanks for all the advice. Using 'non soft' solder on the central locking ECU fried the door/boot units. What a donkey! School boy error, I should have known better. Result? I've disconnected all the rods and will use the key to lock/unlock the doors. Thanks again for your input. JJ

[Brianmoooore]

Have you checked that you can open the fuel filler flap?

[jmec]

Fuel filler cap's fine thanks. I'm assuming the C/L motor is as dead as the rest and has locked up on open! Cheers JJ