I have a 2002 ML320 that has just developed a new problem and I'm wondering if someone has had a similar problem and can provide some insight.
The other night after picking up a friend... the SRS light came on... My Radio started flickering on and off and the same with my headlights.. I began to lose power drastically and about 5 minutes later I find myself on the side of the road and the car wont start. After multiple attempts.. even the interior lights disappear. I immediately assumed there has to be an issue with the alternator.. and a gentleman offers to give me a jump. The car starts.. but immediately dies again 2-3 minutes after he disconnects.
The next day I replace the battery with a new one I bought from walmart. Voila.. it works.. I drive the car around for a bit.. (10-15 miles)... park it at home.. come our 2 hours.. later.. drive another 2-3 miles.. BOOM. SAME exact thing.
I'm thinking.. this has to be a faulty battery or something. I get another one.. voila.. it's fine again. Drive around for about 20 minutes and boom.. dead again. Battery is dead as a door knob again.
Should the car battery DRAIN in 20-30 minutes? I spoke to a repair technician on the phone and he mentioned that even if the alternator were bad.. the car wouldn't drain that quickly.
On a unrelated note (I hope).. the car has been misfiring on cylinder 1 (Code: P0301) for about a month. I replaced the spark plugs immediately after it started, but it's still misfiring..
I hope someone can provide some type of help here.
Also... I forgot to mention. I did lose the cd changer in the car. It's stopped working a while ago.. and the sound system has been cutting out off and on for weeks.. like it would play for 30 seconds.. then there would be a 5 second pause... then play again. Almost like it's shorting.. Do you think this could be related? Would a short cause the battery to drain quicker?
Have you check if there is any current drain when the engine is off and with the key in the off position..? If there is any significant current drain, then you have a short somewhere, and then you will need to pull/disconnect out feature fuses/plugs to try to pin-point what/where is the problem. Or you can take it to the MB dealer to see what the computer feedback is..
Have you measure the charging DC voltage of the alternator..? Should be around 13.0 to 14.5 Is there any large AC component in the charging voltage..? (AC not being converted correctly into DC).. AC voltage/current will confuse electronics..
Batteries will not drain while you are driving unless the alternator/rectifier/voltage regulator is not working properly. In the same way, batteries will not drain when the vehicle engine is off unless there is a short/leak somewhere..
Good luck..
Ac
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2005 ML 500
Black, 18" AMG Wheels, 285/60R18 Falken Ziex ST/Z + Bi-Xenons(+ Drew's e-code mod), Yakima roof bars. Former vehicle 2001 ML 320 with 108K miles, when traded, and a large repair/defect history.
You will need a fully charged battery and a digital volt meter to perform these tests.
Shut down everything that is working in the truck...........radio, blower motor, wipers, ..............everything. Close all doors and hook up the volt meter to the battery. You should be showing voltage somewhere in the range of 12.5 or better. Start the truck and look at the voltage and if you have a properly working alternator the voltage should read 13.5 volts or better. Then turn on the wipers and the headlights. If there is a significant drop into the 12 volt or below range, you need an alternator.
If the alternator is not the problem, then you have to check for a drain on the system. Everything on the vehicle must be shut down, all lights off, all knobs turned off, all doors closed, and the key out of the ignition.
Remove the negative battery cable from the battery and connect one lead from the volt meter to the negative post on the battery and connect the other lead to the end of the battery cable. A voltage reading will appear. ANY READING OVER 11.99 volts means you have a drain on your system. Do not worry about any reading under 12 volts which is considered a parasitic draw (components that need to be powered when the truck is turned off).
We had a similar story. We had to replace the alternator ($181 + core from Autohaus AZ - as opposed to $1300 from dealer).
We did get a new battery under warranty though as the alternator killed it.
There is a TSB regarding alternator voltage regulators - do a search.
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Geordie
VA USA
2002 SLK32///AMG
1990 300CE-24 with 17" ///AMG AeroIIs
2002 ML320 (Wife's car)
It looks like it might be the alternator. I'm thinking of trying to replace it myself.. it's just right there in the front. It looks incredibly easy to get out and replace... but I know I must be taking the entire process too lightly. Is it really as easy as it appears to be.. or is there something i'm missing?
Linear Mode
