battery drain /alarm

[misfire84]

I have had an intermittent battery drain on the car thaught i solved it and its came back .. on investigation there is a drain of 0.97A then whilst conecting and disconecting things the alarm went off , reset the alarm with the key fob and the drain is now back to 0.04A ( i think normal) .. so I think it is the alsrm module not switching off can any one tell me where the offending box is located

 

[cyberflex]

I had an issue with our September 2001 C320, that has electric seats/memory on both sides, the seat controllers were at fault, I do not know which side, because as soon as the drain happened once, then again, I applied the 'US' fix to both controllers and the drain issue was dealt with. The fix involves cutting the permanent live feed to each seat controller and tapping it into the ignition live feed of each seat controller, you will be left with the cars loom side of the permanent live which should be heat shrunk for safety as it will still be permanently live. Both my 'taps' were soldered and heat shrunk, no effect on memory, just lost easy entry feature and ability to move seats with key OUT of ignition. Also noticed overhead console fan seemed to turn of after 30 secs after locking car and 30 mins without. CANBUS related.
Jon
Ps Alarm siren located 'under' nearside front wheelarch guard, I think.. Also, it is quite normal for siren to become active if you were connecting/dis-connecting stuff, so maybe, but not definately, rule that out.

 

[misfire84]

Thanks for the ideas the seat modules are disconected ... also i have disconected the overhead console .... I think it is can bus related is units not going to sleep when they should do. ie the radio or alarm ... another clue is the current drain will be there if the radio flashing red light does not come on and the drain goes if the radio light flashes ...

 

[cyberflex]

Right then, remove audio10/comand, remove cd changer, see if it goes away.
After I got rid of the drain I got rid of as much stuff using CAN protocol as possible, I had gathered info from reading US stuff, that as well as OCP, electronic ignition switch and relays in front/rearSAM's, cd changers, audio10, comand units, that were ageing, could cause the CAN not to sleep.
So after I knew my seat fixes had done the job, and the fact that I and others wanted bluetooth/USB, I removed the audio 10 Tape deck, removed the glovebox cd changer and fitted a single din KDC-BT8044U, I did not use the can hi and can lo in the 10 pin iso, instead I tapped into the cigarette lighter feeds for ignition and illumination feeds which were not present in the power 8 pin iso that went to the audio 10.
I could have used an aftermarket canbus module to get these and other signals as well as a stand alone Kenwood module for steering wheel controls, which would have picked up the CAN HI and CAN LO on the 10 pin iso, but my thinking was and still is the less on a pre-facelift W203's bus network the better, when it comes to battery drain issues.
Hope this helps mate.

 

[misfire84]

ok thanks do you know where i can get my can bus analysed to find this fault .. the dealers via the star systems .... any one

 

[cyberflex]

Yes, although faults e.t.c. can be read/cleared with snap-on, win-star, bosch, sun, e.t.c. Star diagnosis is a sure way to test modules. Although I believe the top end Bosch stuff, is pretty comprehensive/specific.
Cheers.

 

[misfire84]

thanks next update it is the can not going to sleep and i have now a srs warning light !! i have traced it to the third plug on the drivers can block now i must go to the dealers

 

[cyberflex]

You have done the hard work, the fact that you now know that by disconnecting the 3 plug on interior can distribution block should allow them to find the faulty node easily.
Good luck.

 

[misfire84]

thanks for the coments the node seems to be the dash/instrument cluster I hate to think how much it will be ? any one know if they can be repaired. for the time bieng I have found a way of putting the car to sleep ..

 

[cyberflex]

Thats not good, when I was researching I remember reading of 1 maybe 2 instances of it being the cluster, I think that was on the US forums, the guy had it replaced, it cost a fair bit, I believe there are companies that repair this exact problem, try these, someone on here was told to use them, they deal with the battery drain issue.
Cluster Repairs UK - Instrument cluster speedometer repair, correction, modification and spares.
Cheers.