vito W639 109cdi battery drain!!!!!!!!!!! urgent

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magic33Lon

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Jun 7, 2017
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2
Car
mercedes vito
Hi. I've got MB Vito W639 53reg.
I own this one for over 7 years. Since last 6 months im struggling with battery drain. Its showing 7amp drain.
Long story short- after heavy rain water in pollen filter. Fluded vents. Water dripping inside.
Ive spoken to some specialist and still no one have found what's causing 7amp drain.
I have removed heater and fan unit.also radio was removed.
after that ive noticed that plastic wall behind radio compartment is getting very hot and after looking all around ive found two cables atached to two bolts. Red and brown which are located at the bottom of central console above airbag control unit. Red cable very hot. Anyone knows what they are for? Im afraid that by disconnecting them i can damage ecu or other units. Mercedes technician in Brentford had no idea what's in there... can someone help me??!!!!! Thanks
 
The large wires in the heater are pre heat, it has an element inside.
 
Hi, assuming you have a multimeter set it to amps & measure output from battery & wait for a few seconds as some circuits are energised when first powered so you need to wait for discharge to stabilise, keep meter connected & remove each fuse one at a time to see which has the most draw (bear in mind it wont drop to zero) this should at least tell you which circuit has a problem, while your checking dont turn anything on as most meters have a 10A limit & you may blow the fuse, also it may be worth asking someone with a 639 if the affected circuit controls anything else as Merc are really bad at telling you exactly what is on each circuit. Hope this helps Chris
 
Hi. Thanks for your reply. All fuses checked by qualified person. Nothing. All good. Its showing on the battery 7amp drain but nothing in the main fuse box. There are 3 fuses under seat but they all good. Also relays checked. Nothing.
My question is can i disconnect those two cables which are located under Central console( behind lighter) above air bag unit. Clearly need some W639 owner who already took apart central console
 

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