Good evening,

I'm new to the forum so please bare with me. I am the owner of a 2001 ML320 with approx 122,000+ on the clock. Recently I've been having a number of issues but the one that truly has me stumped. I've been having some batter issues where I would need a jump start for the last week but Several days ago my W163 would start up with no problem and stay powered while driving, however she would not switch gears as I accelerated(I assume Limp mode). I drove her home and she would. It start the next day with a jump. Took her to my independent mechanic and had the codes pulled. Changed a coil and a couple plugs and the limo mode issue seemed to be fixed. So here's my issue. Drove to autozone and purchased a new battery and had my mechanic install it today. All seemed well. The car started up and I drove home. Parked for a couple hours and went back out. Car started right up. I drove approx 40 miles with no issue, that is until I went to park. Car returned to limp mode and would. It switch gears. I shut the car off restarted and everything reset. I sat in the car for approx 30 minutes with the engine running then turned her off. When I returned to the car and turned the key all I got was a click click click... went in my trunk and got my trust jump pack and gave her a boost. The car started with no hesitation. I drove home the 40 miles with little to no issue (radio would go in and out occasionally) no battery lamp light nothing. I parked at home and shut her down. And of course out of curiosity I tried to star let her up and.... click click click. The alternator was replaced back in January of this year. My question is how can a brand new Duralast H8 - AGM be dead in a matter of hours? I'm not very handy with a wrench so please go easy on me. Any help is appreciated.

 

Thank you for the reply. Yea I spoke to my mechanic this morning and he said the same thing. I won't be able to bring it today so it will have to wait until tomorrow. I will return with an update .

 

moved to W163 forum...

 

Sorry if I posted it in the wrong section.

 

So I spoke with my mechanic today and he believes it's the alternator. I would usually agree with him but it doesn't logically make sense. Forget the fact that I just bought a alternator in January. My issue is, if the alternator is shot, 8 would just be running off the battery. Granted this is a new battery, but even with my old battery the car would stay on and running for hours as long as I didn't shut it off. So my question is, if the alternator was the culprit, wouldn't my car lose all power while driving?

 

With the key out of the ignition and in your pocket, remove the neg. battery cable first then the pos. cable and clean both cables inside and out with a small wire brush.

Then clean both battery posts.

Then reinstall the pos. cable first and then the neg. cable and tighten them down.