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Old 07-03-2002, 11:18 AM
amptique amptique is offline
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Join Date: Jul 2001
Location: Olathe, KS
Posts: 40
Angry New alternator wierd idiot light behavior

The alternator on my 85 300SD finally died so I replaced it with a rebuilt one. I also replaced the alternator wiring harness. Since replacement I am getting some strange behavior with the "idiot lights" and with charging voltages. Upon first turning the ignition switch the antilock light and glow plug lights come on but the battery and brake idiot lights do not. After the engine starts the antilock light stays on. At this point the voltage at the battery measures 12.3 volts at idle speed. If I rev the engine to about 2300 rpm (either in park or by driving) the antilock light goes off. The voltage at the battery now measures 13.8 volts at idle speed. The antilock light will stay off until the engine is shut down and restarted. I had a spare voltage regulator so I tried replacing it -- no change in behavior.

Any help would be greatly appreciated.

Current Vehicles:
1990 Mercedes 300SE (147,000)
1985 Mercedes 300SD (203,000)
1983 Mercedes 240D (167,000)
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