2002 C320 Electrical Oddities

[bbocquin]

Hi All,

Hoping can get help here before having to take to dealer.

March 2nd:
On road trip "Undervoltage Consumer Defect" warning appeared in LCD.

Went to nearest gas station & they checked battery. Was low on cold crank amps so replaced OEM battery. (car has 46K miles) Had to reset "ESP" warning myself after reading owner’s book.

March 4th:
Noticed toggle switch for moon roof isn't working now.

March 8th:
"Undervoltage Consumer Defective" warning with the battery icon appearing in LCD again.

Gas station swore they checked alternator although never saw them hook anything up to it.

Coincidence about toggle switch or related to having battery replaced by someone who really didn't know what they were doing.

(When "mechanic" couldn't just lift battery out, he tried taking a *pry bar* to it! Had to tell him there was a tie-down down. He'd need a socket & extension.)

Maybe hard to get good help nowadays...

Question then. Battery is draining & toggle switch inoperative because chip has not been reset? Based on what I've read on some earlier threads, something isn't "going to sleep"?

Can I reset chip myself w/out going to dealer? (If resetting chip is in the book I couldn't find it.)

thx in advance for any suggestions.

[MarcusF]

Remove a battery with a "pry bar?"

Hmmm. It may be time to consider a real mechanic. The fact that they tested the alternator without using any equipment might be worrisome as well. Hopefully that doesn't mean they disconnected the battery from a running car. That wouldn't be good. Wouldn't be good at all.

At any rate, a trip to the dealer may be of some benefit. When mine was at my local dealer last summer, they ran the VIN and decided my voltage regulator should be changed. The voltage regulator never gave me any sign that it was bad. However, if Mercedes Benz says the history of 2002 regulators like mine indicate it could use an upgrade, and they want to do it for free, how can I refuse?

[psenders]

Why would that be bad since the battery is only used to crank the engine and the alternatior takes over to supply power and charge the bat.

[bbocquin]

Thanks for reply.

And yes, the “Uber-Mechanic� (able to tell alternator’s good without any equipment) should’ve been a dead give away. Then when he got out the pry bar…Yikes!

�I don’t know—It must be stuck in here.�

Yes, tie-down’s tend to do that…

So even though it’s going to be pricey, going to dealership is sounding better & better. One phone call was all it took for one of their tech’s to come on the line and tell me how to re-set moonroof switch. According to him, it very well could be something remaining “on� when it shouldn’t. Bring car in so they can take a look and he’d “flash it� (whatever that means) & install latest software update from Mercedes.

Maybe I’ll be able to laugh about this later. You hear horror stories about “roadside rip-offs�—just never thought I’d fall for one! 180 miles from home—should’ve just driven on in—but hindsight’s always 20/20.

Thx again

[johnamoss]

MB roadside assistance would replaced your battery at MB $$ charge for battery only; no crow bar needed!

[Jayhawk]

Any time power is removed systems have to be reset, and most of the time you can reset them yourself. Read your Operator's Manual for specifics, but I believe one way to reset things is to turn your steering wheel full left and hold it there for a few seconds and then turn it full right and hold. It might right and then left and I'm not sure it matters, but please read your manual under disconnecting your battery.

[sunman]

your sunroof needs to be normalized. It's not related to the battery drain. Check your owners manual. This has to be done everytime a battery is disconnected.

[Jayhawk]

Another "fix" for this type of thing is to turn your steering wheel firm to the right and hold it for a few seconds and then firm to the right and hold. Try that if the other thing doesn't work... But check your Operator's Manual for the best information.

[nalee]

1st bring it to some one who knows how to change a battery . 2nd chack to c if ure alt is ok. more likely be ure seat module. c class are known for defective seat control modules causing current draws which causing ure battery to die.