Thread: Dead battery
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Old 06-27-2002, 06:19 PM
ctaylor738 ctaylor738 is offline
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Join Date: Apr 2000
Location: Falls Church, VA
Posts: 5,316
My normally dependable 300E started having some dead battery electrical problems a couple of weeks ago. I replaced the battery, since it lost its charge sitting on the workbench overnight.

After driving the car yesterday, it would not start this afternoon. 10.48 volts. Charged it a bit and got it started. Got the following:

Idle 12.98 - 13.10 v
2000 RPM no load - 13.50 v
2000 everything on - 11.5 v

Tested across the positive post and wire. Could not detect a draw, but this may be due to DMM skills or lack thereof. Poked around and discovered the trunk light bulb was very hot. Pulled the bulb and will see if that solves the problem.

Two questions:

1. Given the readings, should I replace my alternator? Brushes and regulator are about two years old.

2. Where is the trunk light switch?

Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe
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