SL/R230: 2009 SL550 no power, can't jump, can't turn ignition key.
#1
2009 SL550 no power, can't jump, can't turn ignition key.
I'm knew to MB forum but have been active in a domestic car club for about 10 years.I am happy to read and learn on my own but I have been reading the last couple nights and think I am now reading in circles from doing searches in the forum
First, I bought the car a year ago at auction, it runs and drives and has some sensor and electrical things that need fixing to get it legal but I'll save those for another day after more research. I have done nothing to the car the year I've had other than start it about 8-10 times and drive it down my street probably about 10 miles worth.
After returning home from a 6 week assignment, I was going to move it out of the garage to get out christmas stuff. There appears to be ZERO power and my key wont even turn at all. The accessory battery (which I didn't know about until reading around here) in the trunk is throwing a fault when I put a charger on it. The front battery says 11.6v but doesn't seem to charge more either. But I couldn't even get power if I tried to jump it. That strikes me as very odd, I should be able to jump it, and get power right?
Before I go spend $300 on a couple batteries I think something else has to a miss here. Even with 11.6v or trying to jump it, shouldn't I get something? When I press the buttons on the key I see the red light come on so I'm assuming my key isn't dead. What am I missing? Is there a security thing causing this?
If I replace the batteries, part of what I keep reading in circles about, it sounds like I disconnect accessory battery (neg, then pos) first, then do same on main starter battery, then put back in reverse order. Then will that prevent codes/normalizing things again?
I found a maintenance manual and operator manual that seems to be of little value in troubleshooting.
Any and all help, even links to go read, is greatly appreciated too.
First, I bought the car a year ago at auction, it runs and drives and has some sensor and electrical things that need fixing to get it legal but I'll save those for another day after more research. I have done nothing to the car the year I've had other than start it about 8-10 times and drive it down my street probably about 10 miles worth.
After returning home from a 6 week assignment, I was going to move it out of the garage to get out christmas stuff. There appears to be ZERO power and my key wont even turn at all. The accessory battery (which I didn't know about until reading around here) in the trunk is throwing a fault when I put a charger on it. The front battery says 11.6v but doesn't seem to charge more either. But I couldn't even get power if I tried to jump it. That strikes me as very odd, I should be able to jump it, and get power right?
Before I go spend $300 on a couple batteries I think something else has to a miss here. Even with 11.6v or trying to jump it, shouldn't I get something? When I press the buttons on the key I see the red light come on so I'm assuming my key isn't dead. What am I missing? Is there a security thing causing this?
If I replace the batteries, part of what I keep reading in circles about, it sounds like I disconnect accessory battery (neg, then pos) first, then do same on main starter battery, then put back in reverse order. Then will that prevent codes/normalizing things again?
I found a maintenance manual and operator manual that seems to be of little value in troubleshooting.
Any and all help, even links to go read, is greatly appreciated too.
#3
I physically have been unable to reach cables to it as its backed into my garage. I can reach the front fine, but not the rear. I may have to clear out the other half of the garage so I can try that.
#5
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Join Date: Aug 2008
Location: Houston, TX
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2003 SL500, 1998 E320 Wagon
Then pull out both batteries and bring it to your local auto parts store. They should be able to test the batteries under load and tell you if they need to be replaced. This is typically a free service. Or you can call MB roadside assistance and they can come out and check the batteries for you and if they are bad replace them at a cheaper rate that MB service would.
Last edited by mkirincic; 12-08-2012 at 05:36 AM.
#6
Wow, embarrassingly enough, it truly was only the rear battery. I can't believe I couldn't even jump it attached the the front battery. But I replaced the rear battery and she came back to life quick. I'm was stressed over a simple problem that on any other car or truck of mine I wouldn't have worried at all about. But this thing was dead dead.