Confused - but that's not difficult

[Wullie 1]

I tracked down a battery drain to the pneumatic actuator for the lock in the passenger door so left it disconnected. The confusing thing is everything appears to work as normal. All doors lock off the alarm fob. Both doors trigger the central locking so what does that connection do, apart from draining my battery? I may be missing something completely obvious but it is annoying me.

[davidwort 0]

I think it tells the control box that the lock has opened or closed fully so the cl pump stops sucking/blowing

[Kevin Bacon 5]

Exactly that /\

[Wullie 1]

Said I was easily confused. Pump stops OK so I guess it's getting the info from the drivers door. Must take the a look at the actuator, it may just be dirt or corrosion that's causing the drain plus it gives me something to footer with. I suppose new ones are about £30,000 from VW if available.

[dr_mat 0]

Interesting. What was the amount of drain it was causing?

[Wullie 1]

I don't know how much the drain was but it must have been pretty high as it killed the battery in less than 6 hours. I connected a 21w indicator bulb between the battery + terminal and clamp and it lit up like Blackpool Illuminations. I made the test lamp lead long enough to reach into the car so it provided some light until I found the fuse that protected the offending circuit, it was the "Let's hide a fuse where no-one can find it" one at the top of the fusebox above the relays. I started by disconnecting components until eventually the light went out again, well fell to a dim red glow which is about normal. Typically it was the last thing I disconnected having started with the driver's door.

[dr_mat 0]

Ah yeah, that's a short somewhere.. lucky it didn't set something on fire..!