B2 CQ Central locking?

[Gaz]

The central locking in my 1987 coupe quattro hasn't worked in about 10 years.

When I turn key in drivers door I do not hear the vacuum pump and the passenger door doesn't unlock.

Also the electric motor for the drivers door actuator doesn't make a sound when you press the button on the fob either.

Any ideas? Be good to get this working again after all these years.

[Hanuman]

I think it’s the same as the ur, and if so-

Turn the key in the drivers door, this directly unlocks the door, and the movement also results in the vacuum actuator rod moving. The drivers door actuator has a built in sensor (item 2 in the attached diagram) which triggers the vacuum pump. The passenger side does not have a sensor built in, and so unlocking from the passenger side doesn’t trigger the pump and central locking. A bit of a cheap effort, imo.

For a 4 door car, it makes a little more sense, but in a 2 door coupe, where the boot is manually released, it’s a bit lacking as an idea. The coupe version is just a pared down version. But otherwise fairly simple.

If there was a motor in your drivers door, it’s likely from an aftermarket alarm. If that’s the case, then you can expect all sorts of hacks.

Many aftermarket alarms, like cobra of the time, had solenoids on each door, triggered from the alarm, which independently opened each door. They were very intelligently connected to the locking knobs in the doors. Often badly adjusted, there’d be odd interactions with the orig8nal central locking, and so the original wiring was frequently chopped to avoid the problem.

Have a look at the coupe or 80/b2 diagram on 7zap, (attached, small markups). You’ll see the layout. It’s fairly easy to follow.

The drivers door card should be the only one you need to open for electrics. Pump in the boot.
Actuators generally fail for perished diaphragms, these days.

[BackintheFold]

Hanuman tells it like it is...

Except I'd start by checking the wiring in the door shut/hinge. They often break when used a lot-or after some years.
And of course the fuse for the pump, and the pump itself.

[Hanuman]

Originally Posted by BackintheFold

Hanuman tells it like it is...

Except I'd start by checking the wiring in the door shut/hinge. They often break when used a lot-or after some years.
And of course the fuse for the pump, and the pump itself.

Actually, that’s true. A bit of a leap, and getting ahead of myself. Basic electrics, 101.
Excessive familiarity, I’ve jumped to the usual next culprits.

[Gaz]

Cheers guys! I seem to recall it stopped working new years eve 2009 when there was a very cold frost in the morning. Went to open with the button and nothing.

[BackintheFold]

Hehe.
1980's Audi's that i owned had a frequent "dead headlight" issue. I got so used to running new cable that I stopped checking fuses.... until of course one time i ran new cable and nothing continued to happen!

Blown fuse and an hour wasted. D'oh!


It is a daft system. Previously I've run more air hose to the driver's door, and re-built the actuator to be air controlled as well as by key. Then connect a remote alarm to the pump and you have remote central locking with the alarm!