Central Locking System

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Drives: 1986 MK2 Golf GTI 8v
Location: Bristol, UK

Central Locking System

Postby eddypeck » Thu Jan 03, 2019 1:16 pm

The original factory fitted central locking system used by VW and Audi of the ear was an air pump type which activated slave actuators at each of the locks. The drivers door had the primary actuator which kicked the system into life.

There's an air pump in the boot cased in a foam block.

There are pipes (windscreen washer size) that go around the car to each air driven slave actuator.

Slave actuators are passenger door, rear doors if a 5 dr. boot, fuel filler flap.

Passenger door slave

The Primary actuator is electric and is in the drivers door.

Driver door primary

Turning the key in the drivers door activates this switch and send the signal to the pump to run. The pump then sucks or blows air around the system unlocking or locking the other doors.

You'll notice a delay from turning the drivers door to the other doors activating. Sometimes this delay can be more if the pump is deteriorating or a small leak is present.

The only electrical parts are the drivers door and the pump. The wire to the drivers door goes through the door shut so could potentially break due to 30 years of flexing as the door is continually opened and closed. The switch itself could be effected from 'shock' as the door is repeatedly slammed - especially if the hinges are worn and the drivers door has dropped.

The pump could have failed from age.

Tests, can you hear the pump operate?

If yes but doors don't unlock assume an air leak and loss of pressure. Check air lines, there are numerous joins.
If you cannot hear the pump check for voltage at the pump. Put a direct feed onto the pump to check pump operation.

If pump is fine and power is at the rear of the car check the switch and wires in the drivers door.

If not electrical then could be mechanical. Inside the drivers door when you turn the key there are a system of metal rods that 1. push up the plunger in the door, 2. unlock the door and 3. run to the primary actuator to 'turn on' the central locking.

The rods will not break, they are metal a few millimeters thick. But they connect with flimsy white plastic ends that are more likely to break.

The same rod system is used for each lock as the actuators are not directly on the locks. If an individual lock is not operating it's likely the plastic clip connecting the rod to the actuator is broken.

orange air pipe in boot, rooted with cable

full system

back of boot lock for CL system, different to non-CL boot lock as there's the extra white clip

Boot lock and lock rod

Dimple on fuel filler flap that engages with CL

Pump with reducing hose

Pump casing inside and out

Fuses and relays are explained in Knowledge Library under F > Fusebox and relays viewforum.php?f=142. CE1 for early cars CE2 for later. Quick check is hazzard switch on dash = CE1, is hazard switch on steering column = CE2, has engine conversion been done = could be any kind of bodge, investigate further.
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