Originally Posted by
mb522xfire
I had a problem with the battery going dead on my 2004. In my case, the A/C & heater blower motor continued to run after the engine was turned off and the key was out of the ignition. It turns out that is was a faulty blower motor resistor, which is bolted on to the blower motor and accessible through a removable panel inside under the glove compartment. The crossfire part is expensive, but I was able to buy an equivalent replacement part for a Mercedes CLK320 for around $65 shipped.
Hi, just joined the forum (from UK) as I'm also having a battery drain problem that got worse when my heater fan also now stays on all the time.
The only way I can turn it off it to remove the fuse, otherwise it's on full blow all the time. The battery drain problem started a year ago (it's a 2004 Coupe/Auto) and I fitted a new battery but nothing changed - the car does however get left unused for a week or more.
Over winter we moved house and it was left outside unused for a few months. I noticed once that either the drain holes down the pillars had blocked or frozen, as the roof lining was full of water after heavy rain, and dripping inside from the light unit.
It has been garaged now for a while and it totally dry, however now I have the problem with the fan on all the time. I talked to a dealer and he said something like the 'SAM unit might need replacing/reprogramming', but my motor experience pre-dates modern 'can-bus' type systems and I don't have a clue on this one.
Someone else did talk about resistors, and I've just taken off the bottom of the fan unit having removed the glove box. There are a few old leaves in inside, and I guess it could have got very wet inside here during winter.
Any assistance with this issue would be great. Do I just need to buy another resistor?
Cheers, Martyn