Battery Draining

[turnipsock]

My battery has been going flat over a two day period.

With everything switched off, there is 4 amps running out of the battery. I then pulled all the fuses out (one at a time) and it was still drawing current.

I unpluged the radio and took out all the inline fuses that I could find and it was still loosing power.

Any ideas what could draw 4 amps?

 

[Derm]

What about the alternater could be a leaky diode.

 

[turnipsock]

I'll give one that a try tomorrow.

I will also have to check the central locking pump as well (though it should be on on of the fused circuits)

 

[tom7035]

I think Derm has hit your problem on the nail.

 

[billythetipdog]

Draining battery

Had a similar issue with my W124 and found the central locking vacum pump was draining the battery over the course of a couple of days, get the pump out from under the back seat and open it up; you'll find a circuit board, check this to see if it has burned out - mine had and was the source of the drain. A competant auto electrician may be able to repair but a s/h one is not too steep at around £40. GSF quoted me £130 new.......! Good luck!

 

[dougtsc]

...boot light staying on ???

 

[turnipsock]

Not the alternator, which is lucky because I don't have any diode sealant.

I'm checking the central locking pump next. It does look it's something like that as current dropped about half an amp today. Then, for no reason, jumped back up to 4A.

 

[turnipsock]

Not the central locking pump.

I'm really stuck on this one.

(dougtc: I've had all the fuses out and it's an estate)

The problem seemed to happen in the wake of a radio replacement, though it doesn't happen all the time.

I'll probably rewire the radio with proper connectors and check it all out. The previous radio had a CD changer but this has now been removed (complete with the six CDs that are stuck in there). I still have an auotmatic ariel. However, I have unplugged the radio and it was still drawing power.

Any other thoughts?

 

[turnipsock]

Now the problem has vanished!

I had been poking around the coil, the radio, the central locking pump and few other areas.

The central locking pump doesn't actually work on my car. I had a look at this a while back and found that the bit of the motor that the brushes make contact with was extremly worn.

I'm going to the scrapys next Saturday to pull one out of another Merc. It's a proper scrapys as he was wearing a vest (even though it is only March) and has a load of tattoos.

I was joking about the diode sealant!

 

[turnipsock]

It was the central locking pump right enough. The problem did seem a bit intermitant which made it hard to find. I have still to get the scrapies with my ever growing list of minor parts though.

 

[turnipsock]

I got rid of the draining problem when I removed the faulty central locking pump. The motor was faulty anyway.

I got another one from the scrappies recently and fitted it. The central locking has been largly restored. The only problem is it doesn't work from the drivers door.

There are three wires that go to the door lock, 12V, GND and the signal wire to the central locking pump. The central locking is triggered by a 12V or GND momentary connection. There are some fairly meaty resistors on each of the signal wires (one for each lock).

My battery draining problem was caused by the drivers door switch being faulty, the 12V is connected across the resistor/ capacitor arrangement on the circuit board all the time.

Does anybody know why there is a separate signal wire from each lock...it's not as if you are going to put two keys in at once and try to open and lock the car at the same time!

My next problem is going to be getting the drivers door lock mech out, I can't get the 3mm thing to turn and there is a serious risk that I will strip this.

 

[pascal]

Does anybody know why there is a separate signal wire from each lock...it's not as if you are going to put two keys in at once and try to open and lock the car at the same time!

I presume its because with certain alarm fobs, you canset it to open the lock on the drivers door only with the first press, and a second press will open the rest. I can do that with my car, but I changed the setting back to all on the first press.

Pascal

 

[turnipsock]

Ah...I had forgotten about the key fob side of things, it's maybe not the lock that is faulty. I had thought the blue wire running from the lock went directly to central locking pump. This would explain why the motor didn't kick in when I tried connecting the blue wire to the 12V.

 

[turnipsock]

I think I have cracked it this time. I was outside and noticed the rear interior lights were on. Slaming doors and playing with the switch made no difference so I guess it is some dodgy wire in the headlining somewhere.

 

[television]

I think I have cracked it this time. I was outside and noticed the rear interior lights were on. Slaming doors and playing with the switch made no difference so I guess it is some dodgy wire in the headlining somewhere.

It will be the switches and do not forget the one in the rear lock on an estate