230TE - mystery battery discharge

[Jumbo Whiffy]

My J-Reg 230TE estate will only run for three days before the battery is exhausted.

A new battery failed to solve it, as did disconnecting the alarm, and my friendly neighbourhood mechanic (not an MB specialist) and his auto electrician colleague had to give up defeated after failing to trace a fault - at least they didn't charge me for stripping and rebuilding the alternator!

So now I have to charge the battery every three days, which isn't ideal

Has anyone ever had anything like this?

 

[Taxing Ken]

Hi

I had a similar problem on a non MB. It took a long time to track down but eventually was traced to a power drain in the ECU. The only cure was a replacement.

I would suggest all other avenues are explored first as if it is the ECU this may be expensive.

 

[television]

A ammeter must be connected up over the battery, care must be taken to ensure that the ammeter is joined up before the battery + is disconnected,otherwise the fault could correct itself, do this and come back with the reading.

Malcolm

 

[turnipsock]

I had this problem on my 230TE. I traced it to the central locking pump.

I think the rotor on the motor gets worn and then provides a path for current to drain through this.

Easy way to test is connect up a meter as Malcolm says. Then, disconnect the central locking pump and see if the current drawn reduces.

If a meter is showing a significant current and it's not the cetral locking pump, try pulling out fuses to see when the current drops.

Does the central locking work?

 

[Jumbo Whiffy]

Thanks very much for all the advice.

Central locking works fine, so may not be that BUT I have very limited ability or knowledge as an electrician!

Will try and get a more competent friend to do the ammeter test - I know what a parking meter is, and I'm fairly sure I can point out the speedometer, but I wouldn't know an ammeter if it walked up to me, slapped me round the face with a bag of sultanas and said: "How's that for a current discharge?"