Electrical problem in 2002 E430 4MATIC - PeachParts Mercedes-Benz Forum

skiier3_9 · #1 05-04-2009, 05:40 PM

Last week, I was driving my 2002 E430 and the BAS/ESP/ABS lights came on, the dash lights went dim, the accelerator quit working and after shutting the car off it would not restart (it also threw a Battery/Alternator malfunction).

I had the battery replaced by roadside assistance (since the battery was original with the car) and everything seemed to be in order.

I drove it 3 or 4 times over the weekend and everything worked fine... However, today on my way home from work I had the same problem (lots of malfunctions and eventually another dead battery).

When the car was running - I did not receive any alternator/battery warnings, however the car won't turn over now.

To me this seems like an alternator or voltage regulator problem. I'm looking for advice on the best way to test either/both...(or ideas on what the problem could be otherwise).

Thanks!

pawoSD · #2 05-04-2009, 06:08 PM

I'd check the voltage regulator first, if its ok, then replace the alternator. How many miles on it?

skiier3_9 · #3 05-04-2009, 06:15 PM

Just turned over 68k this week. What's the best way to check the VR?

pawoSD · #4 05-04-2009, 06:24 PM

check the voltage at the battery terminals with a volt meter when the car is running, it should be between 13.7 and 14.3 volts or so. If its less, then there's a problem. You can also remove the voltage regulator from the back of the alternator itself and check the brushes for wear.

skiier3_9 · #5 05-04-2009, 06:29 PM

Since the battery is now dead (and obviously not charging) - I'll take the thing off an have a look...

pawoSD · #6 05-04-2009, 06:41 PM

Do you have a charger unit you can charge the battery back up with? They can be had pretty cheap. I'd charge it back up and check the voltage when running too. If the brushes on the regulator look good then it might just be faulty, or the alternator itself might be faulty.