CLK 350 Battery Issues

Try pulling out the fuses for the front seat control units. They are on the fuse panel behind the headlight switch. If you notice your battery not dying anymore put one back in and try it again. Chances are one of the modules is faulty causing other control units in the vehicle to stay turned on thus killing your battery.

i bought a new battery it was faulty,,also your car alarm drains power 2 weeks is along time

This has driven me nuts for months now. And it is clearly a fault with this car!! It cannot be coincidence that so many of us have battery drain problems!! I have a trickle charger, I have had the RAC out (couldnt get into the boot myself of course because manual keys dont work!!), bought a new battery and within 2 days completely dead!!! I am getting rid of the car and suggest everyone does same!!

Mechanics love when customers give up on a car like that. I'm driving an S class a customer gave up on. All it needed was two fuses. Remove any aftermarket electrical consumers in your CLK. One of the biggest problems I see are tracking devices which are old or incorrectly wired into the vehicle. After that I'll guarantee one of the seat control modules is the problem. See my earlier post.

I purchased a NEW ($155,000) CLK 350 (2010 model) it has had two NEW batteries in two years....now going to get its 3rd new battery in under two and a half years... The Technician told me it is problem with this model because of all the electronics its drains the battery and Mercedes have had lots of problems with them.. A solution would be good....

Well after a complete nightmare with this problem I now have my solution. My garage people fitted a battery turn off switch!! Sure theres a proper word for it, but it is located in the boot and I simply turn it and it disconnects everything. Nothing to drain anymore.....so far it has worked well. When they first fit it, they closed the lid aarhhh!!! instantly locking it of course. Needless to say they couldnt get back in with the manual key (they never work!) and they had to fit a new lock! Outrageous price from mercedes but they sourced a second hand one with its own key. But since there is now nothing to drain I leave the boot just slightly open so that I can always have access - not trusing any keys any more. I dare say it would go dead after some time but I have a trickle charger will I will also attach now and again to keep it topped up. Sorry for such a rambling reply!

the manual locks are tricky, but they should have done a Parasitic Draw test, removing one fuse at a time, determining which one is using the current, glad you have a quick fix, but I agree, especially in the C-class, there have been NUMEROUS electrical issues, that have never been worked out, sadly, a HUGE Mercedes fan, will say that series is garbage, :( anymore questions feel free to let me know..

both my c class and s class have this problem , battery drain, i have a trickle charger that i have been using, i will try the seat fuses on both cars , thank you

I hope it works, s-class has a computer which stays active, (pending the year)...let me know and i can help with further diagnosis

I am surprised to hear about the problems you have with CLK. I have a 2008 CLK cabriolet sitting in my garage since Nov/2013. I started the car only 3X during this below 0 temperature in Toledo. I never had any such problem, in fact, this is the most reliable mercedes I ever had.The battery is original, This has only 19K miles, only changed rear tires recently.

By the way, there is no 2010 CLK. This has been replaced by Eclass cabriolet costing over 70K. in 2010.

Your battery draining issue sounds like an alternator fault. I had the same problem on a Vauxhall (GM) Calibra and on a Volvo years ago. I now have a CLK350 (2006) for the past 4 years. The battery just failed this morning on my way to work!! ouch. Will spend about £80 on a new Bosch one. Kind regards, VJTheDJ.

Hi everyone......after being driven nuts by this problem my garage fitted me with a total immobiler (for the battery) so that it cant drain anything!! I do hve to leave the boot resting on something admittedly, to stop it from shutting....But it has worked a treat!! Its actually in the boot, and I literally turn it when the car is going to be standing. I have just got the car out again after four months....turned my key and hey presto%&!!!! Started first time!!!

hi i have clk 350, had it for since 2008, and just start haveing problem with battery, no dont drive it as much just this year BATTERY did not start, recd my 2nd jump, but dont want to get stuck, try to start it every day, but today car started but no liights until it droves for 20 min ,is it battery or fuse.

What year is your CLK. Mine is 2008 cabriolet. Had it for 6 years and has 22K miles. Most of the winter it stays in the garage starting may be once a month.Battery is original, never had any problem.

I would say it is battery. How old is the car and/or battery? If it happens again, I would definitely change the battery.

Omg these cars have so many problems with the battery i have 2006 and 2009 clk 350 and they both have problem with draining the battery i took the 09 to mercedes benz place and they told me it was my amplifier that keeps draining my battery and they took out the fuse and i haven't had any more problems with that one now the exact same problem has happen with the 06 this is crazy to spend so much money on a car which u hardly ever drive because of battery issue

Am I the only lucky one to get a 08 CLK Conv? I bought it with 11K miles in 09 and never changed the battery and garage it in the winters, starting once a week or two. It just starts "boom". My 560SL had an 11 yr old battery and started just like that with no problem. My wife's RX 400H needs battery every 3 or 4 years. Is there any correlation between a person and battery or a person and car? I am reluctant to replace it by GLC(thought). But if somebody pursues I might do that.

All of you should consider a class action suit about battery problem. And should file complain to FTC. Federal agencies do not work as well as it supposed to. But if there is enough and frequent and loud complain, the agency may wake up sooner than later.

FWIW. I recently bought a 2008 CLK350 with 28,000 miles, that had been well maintained by its second owner. He drove it mainly from his home garage to his office garage starting in 2010, and stopped using it after a few year; he just kept it for special occasions or to keep it in good shape (he had a second Honda for normal use). Well I found out that the battery would not start the car if left unused for more than two weeks. Turns out replacing the battery was all that was needed, knock on wood. The battery had not been replaced ever previously.

I am now on my 2nd CLK. Battery failed but the car is 10 yrs old. I don't see any problem other than the expected failure rate. As I mentioned on my last reply with my first CLK. It sounds like an alternator fault if it drains whole off. I am a heavily qualified electronics engineer so maybe I am biassed on my opinion.

10 or 11 years on a battery is pretty much unheard of. Class action lawsuits get thrown around in these forums as if they mean something. In reality if there were a successful lawsuit over batteries it would end up with the lawyers getting millions and the owners of the cars getting a coupon for $10 off their next battery. MB car prices would go up to cover the cost.

It seems many CLK owners do very low mileage. I only drive to the supermarket on weekends...lol.

I have a tractor that is used on occasion and the Interstate battery is at least 10 years old. I can't remember when I bought it. My Jag battery did not last that long but I nursed it along for at least 8 years.

Could be, there is a small light left on. Or Clean the convection where the negative wire is attached to the body or frame. MBA like to connect the ground wire to painted body. Clean the paint off when apply a small bit of vaseline between the connection. This is a solution for most electrical problems.