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What happened

879 Views 8 Replies 5 Participants Last post by  [email protected]
My 260e sat for a day. Took it out this morning for a drive and on the way home the rpm gauge went crazy, the SRS light came on, the radio turned on and off continously and the blinkers stopped working. Made it home and turned off the car and now it is completely dead.

Is it the battery or the alternator?
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· Registered
Mercedes 1986 300E 165,000 miles
110 Posts
Check your battery first with a voltmeter, you should get around 13V. If it is low, charge it 100%. Once fully charged, try it again and if you get the car running, check battery voltage to make sure that it is charging. If not, you need to replace the alternator.

· W124 Moderator
86 190E 2.3L 16V, 95 320TE 02 S500
13,357 Posts
Just to add a little to what's already been suggested. A fully charged battery should have 12+V showing on the meter. When the car is running, the meter should have a reading in the neighborhood of 13.6 - 13.8 volts. If not, then it can either be a bad alternator or more likely a bad voltage regulator. The voltage regulator is mounted on the back of the alternator and held in place by two phillips screws. A very, very easy DIY change. New ones can be had at NAPA for less than $40 or you can purchase on online from a number of sources for less. and are two that I use and both offer superb service and selection.

Good Luck,


· Registered
1985 190d German Cockroach 2.2 M5 395k miles 2004 C240 Wagon Non-4-matic
282 Posts
ovp, nss, fuel pump relay, and voltage regulator

I put off a repair for too long by starting the car in neutral because of the neutral safety switch ... good interim solution, til it left my wife stranded : ( .

I believe that by starting in neutral too much I killed the OVP (also a repair postponed) which finally killed the car on the road. To troubleshoot, plugged in a spare OVP from a Junkyard and it fired right up. Ordered a new one from

I also replaced the fuel pump relay.

Replacing the voltage regulator just to be sure.
Goes to show you that one thing leads to another.... a snowball turns into an avalanche. Anyway replaced all and she's back n the road. A word of warning to the wise.
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