W124 central locking issue - electrical drain

[verysideways]

Wonder if you guys (and girls?) might be able to help with this.

My car has an electrical drain which will flatten the battery in about a week. Having gone through the fuse box with care, the only two circuits with any draw when "all off" are the clock and the central locking circuit.

Now funnily enough the central locking circuit doesn't work that well:
1. If i lock or unlock the car using the key in the passenger door, all the locks work as expected (so i think the vacuum pump is working correctly).
2. If i open each door individually the interior lights come on and go off as expected (so i think the door switches are functioning correctly).
3. If i lock the car i can unlock it with the IR remote, but...
4. I can't LOCK the car with the IR remote.

So - does anyone have any suggestions as to how i might trace this?
I could do with a wiring diagram for the central locking for a start huh?
And where is the central locking vacuum pump?

Any tips gratefully received.

 

[television]

http://www.autolib.diakom.ru/CAR/Mercedes-Benz/1994/E320/SYSTEM WIRING DIAGRAMS/4953.pdf

http://www.autolib.diakom.ru/CAR/Mercedes-Benz/1994/E320/SYSTEM WIRING DIAGRAMS/4922.pdf

I think that the pump is under the rear seat

 

[Bolide]

On a W124 estate the pump, comfort module & RCL locking brain are under the o/s/r seat

The RCL brain is coded to the keys. On most cars (those with DAS excepted) nothing else is coded to the car so can be swopped

Nick Froome
www.w124.co.uk

 

[The German Flower Pot]

must say both of my w124's are terrible battery wise

i charged both for 30 hours with a mains trickle charger and left them and after about 8 days both were dead

changed batteries on GFP 2 about 3 times in 5 years and its always been the same and now ive got 2 they both do it

1 has an all singing and dancing alarm and the other has nothing yet they are both bad

 

[television]

So simple these days,, a clamp meter can be bought for £30, and you know instantly if it is the battery or the car

 

[Andy Cottrell]

Hi,

My W124 Estate pulls 20mA from the battery when left parked and locked. Alarm not on. I haven't investigated which circuit(s) pull the current, I've just accepted that after a few weeks without use I need to charge the battery before attempting to start it.

 

[mattkh]

Hi,

My W124 Estate pulls 20mA from the battery when left parked and locked.

20mA is nothing. I bet that is the central locking pump doing what it has to.

 

[biglips]

I have an update on the original post, having recently bought this car.

The central locking symptoms are unchanged (ie cannot lock the car with the remote, but unlocks remotely OK and central locking works fine if engaged manually with key)

BUT if I put the key in the boot lock and lock the boot manually, then press the remote button with key still in place, the red light flashes and the central locking engages perfectly!

I dont understand can anyone throw some light on this??? Any help much appreciated

 

[television]

What is the car please

 

[biglips]

It is a w124 e36 AMG estate (1995)

 

[grober]

There should be an IR receiver on the rear panel below the boot. It may simply be a weak signal from the remote. Sticking the key in the lock may get the signal to the control unit more effectively.

 

[grober]

Wonder if you guys (and girls?) might be able to help with this.

My car has an electrical drain which will flatten the battery in about a week. Having gone through the fuse box with care, the only two circuits with any draw when "all off" are the clock and the central locking circuit.

Now funnily enough the central locking circuit doesn't work that well:
1. If i lock or unlock the car using the key in the passenger door, all the locks work as expected (so i think the vacuum pump is working correctly).
2. If i open each door individually the interior lights come on and go off as expected (so i think the door switches are functioning correctly).
3. If i lock the car i can unlock it with the IR remote, but...
4. I can't LOCK the car with the IR remote.

So - does anyone have any suggestions as to how i might trace this?
I could do with a wiring diagram for the central locking for a start huh?
And where is the central locking vacuum pump?

Any tips gratefully received.

Common fault is the boot interior light staying on due to faulty switch.

 

[biglips]

There should be an IR receiver on the rear panel below the boot. It may simply be a weak signal from the remote. Sticking the key in the lock may get the signal to the control unit more effectively.

Thanks Grober. Unfortunately I do t think this is the problem as all 3 keys have the same problem and the range for unlocking using the remote is very good! I will check the rear boot light although the battery drain has not been a problem for me since I have owned the car.

Tom