with key in pos 2. I just replaced the 70A alternator with 80A. I changed the connectors etc and all was for about 3 hours of running, a good 13.96 volts idle. Then, it quit.....No charging. BUT....1) Hi beam light works when selected 2) Bat light will not work, bulb checks good 3) BRAKE light comes on when parking brake pushed on. 4) Coolant QTY light comes on when switch is bypassed and grounded. Puzzling I guess I need to know a) What causes the idiot lights to work when the individual system is tested, but NOT to work when the key is in pos 2. b) Why can't I get the Bat light to come on with a brand new (rebuilt) Alternator??? I also replaced the Ignition switch to rule it out..........HELP!!!!!!! BTW The right side lights work, ABS, o2 sensor, SRS.......its an 86 300E 5 speeder.......

I am running outta beer...........

For what it's worth, I had the same symptoms on my 82 300D a few years ago when the alternator failed. For some reason, the BAT light did not come on when it failed, but all the idiot lights on the left side would not come on in "test" mode when starting the car. I thought it was an instrument problem until the battery went dead. When the alternator was replaced the lights worked normally again. I assume the alternator had some unusual failure mode that did not cause the BAT light to come on (an internal short maybe?).

Did you say your alternator had stopped charging when this happened? It's not that unusual for rebuilt alternators to fail right away. I would test and/or exchange the alternator and see if the light issue fixes itself.