Jordan7589

Had it in the wrong section. Here it goes:


This has been a problem for me for the past 4 weeks or so, i bought it about 8 weeks ago, figures. The car dies the first time, i had it jumped, it worked fine, i started it fine for the next 2 days. then when i go to start it the 3rd morning, it wouldnt start again. i had it jumped again, and replaced the battery with a new one. it started fine for the next 2 weeks. it died again less than a week ago, i was pissed now, so i decided to bring it to the dealer because my local shop that does european cars (audis, benz, vw, bmw) said he wouldnt know where to begin to find the problem. the guy did use a voltmeter and saw that the battery was going down even after i shut the car off, but he didnt know what to do, so i left there asap. i went to the dealer and they had the free one hour diagnostic so i decided what the heck. i left the car there for 4 hours and came back. they said my driver power seat was draining the battery and they wanted $650 for the module plus labor which is 120 an hour. i took the car back and used this guys DIY on rewiring the seat so it turns off when the car is off: http://www.mymbonline.com/forum/viewtopic.php?t=23552

It started fine for the past 3 days, and now it wont start again. before i jumped it this morning, i used my voltmeter and tested the battery, it says 11.15 volts which i figured is plenty since the battery should be at 12 volts when the car is off. when i first go to start it, the car will click then then slowly crank for half a second. then after that, it will just click when i go to start it, and eventually it will stop clicking altogether. last time i did it, i had the jumpers in the trunk and i couldnt even pop the trunk. any suggestions on what the problem is? i thought it would be the alternator but it seems like the battery is holding a charge because its at 11.15 volts after its been sitting overnight. PLEASE HELP ME OUT, if this car wasn't so fast and fun to drive, i would have sold it alrerady.

Jordan7589

I spoke with my other mechanic and he said if the car is under 12 volts, it wont start. Even at 12.0, it's still very low. I'm thinking maybe that DIY guide didnt fix the problem and maybe i should try TEMJINX2'S FIX. What do you guys think? All i did was snip the red wire on the plug that has 3 wires (black, red and brown), i snipped the red wire then use a tap in wire connector and put the red snipped red wire in and then the black wire on as well, so basically the red wire was tapped in to the black wire. My job is getting pissed, when i go to start my car to go to work, it wont start and i have to call out.

P.S. i couldn't understand TemJINX2's DIY guide, it was kind of confusing but i knew something had to be up when his diy guide looked alot more complicated then the one i used which consisted of snipping a wire and putting a tap in wire connector on.

TemjinX2

the other fix is fine. I tested it on my car and it works as well. You might have a overhead module power drain. if you have command, some times the command fan will stay on and drain the power. The command fan can be fix with a bios flash from the newest navi dvd.

You can pull the fuse in the rear sam to turn off the over head module.

Also, i would just take the battery to be fully charged at autozone or kragens. The front sam doesn't like being jumped too much, so you run the risk of damaging it.

The front and rear sams in our cars are ridiciulously expensive.

Jordan7589

thanks guys. i let it sit from 3am til 1130 am, so 8 and a half hours. i went to test the battery and it shows 12.35 volts. does that seem like normal range? i hear 12.5-12.8 is more in the normal range. i drove it last night from my house to drop someone off then back to myhouse, about 10 miles total, so im not sure if 10 miles was enough to fully charge the battery. what do you think?

TemjinX2

12.5 is about normal. so i would try to drive it around little more.

Jordan7589

Sounds good. BTW, i reconnected the wire that i snipped off from the first DIY guuide, it was the big red wire on the plug with the black brown and red wire. i did your DIY version yesterday and thats when i went to check it today and it showed 12.35. I drove around 35 miles today. im going to let it sit overnight and see what it reads in the morning. im hoping it will stay over 12v. Mercedes did say that the driver side control seat module needed to be replaced because they pulled the fuse for the seat and thats when the power drain stopped. maybe the other DIY guide didnt work? We'll see. Thanks alot, i appreciate the help.

Jordan7589

Went to test this morning at 12pm. Has been sitting since 1am, so 11 hours. It now reads, 12.17 volts which is on the low side. I know the alternator is supposed to maintain the charge on a battery, so would it be a good idea for me to buy an actual battery charger to return the charge to full before putting it back in the car. I heard that the alternator isn't meant to be used for charging the battery, simply just to maintain the batteries charge while the car is running. I haven't charged the abttery itself since i made the fix to the driver seat. Am i wasting my time with this or do you guys think theres something else wrong?

buffyclk500

i would look at the cps they go bad

Benzboy13

i had this problem in my old 2001 c320. Ended up being a faulty module in the passenger door. An indicator of this was a flashing side mirror turn signal randomly throughout the night. I was lucky enough to have this "signal" as to what was wrong.

c32=slow_lol

its because you need a bmw...