This is a relatively minor issue but though smoeone might have some insight. I have a 1990 300sl. On startup, the charging light illuminates and stays lit until I give it a little rev. Once I've been driving it, if I come to an idle the seatbelt light will flash if I have a few accessories turned on. If I turn the heat on full blast, put the seat heaters on etc., the seatbelt lamp lights and stays lit. No problems when I have my foot on the gas... Any thoughts?

sounds like power issue... have u checked the voltage of the battery at cold, idle, all electrical on and foot on the gas?

I had that problem just before my car stoped and waiting for tow truck. turn out my alternator was completely gone and have been running on battery up until the last juice!

The thought has occured that this is a voltage issue but there are none of the usual issues. (variable brightness on headlights) I will check the voltages ('bout 12.8 - 13.5 right?) I wonder if there is an under-drive pulley on the alternator...

mine is 12.75 when the car is off. I.e. the battery by itself.

when the engine is on with nothing else, my alternator pumps 14.4v.

when air/con is on together with lights and radio/CD, i think mine reads 13.5 or something.

hope this helps.

I guess my question is related, don't want to steal your thread, but sometimes when I am just driving down the road my seatbelt light will come on for about 2-3 minutes then go off. I am speaking of my '79 300SD. Could it be the voltage regulator on the back of the alternator?
Thanks
David

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2000 Honda Accord V6 137k miles

1972 300SEL 4.5 98k miles

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