I put in a new voltage reg , but the battery light is still on. I put a volt meter
on the battery. It drops to 11 volts when starting then back to 12 after it
starts. When I hold it at 2200-2500 RPM the volts don't rise at all. What
else can I try?
Thanks Jay

Did you have 13.5ish volts before you put in the new regulator?

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Seth

1984 300D 225K
1985 300D Donor body
1985 300D Turbo 165K. Totaled. Donor Engine. It runs!!!
1980 300SD 311K My New Baby.
1979 BMW 633csi 62K+++? Dead odo

yup. I charged the battery put it in it had 13.2 volts. The volts drop when starting then go back. but the battery light stay on. If I turn on some stuff the volts will drop..

It appears that you had a voltage problem prior to replacing the regulator, correct? Now, with a brand new regulator, you still have no alternator output?

If so, then the alternator itself may need to be rebuilt or replaced. The only other possibility is an improper cable connection to the alternator.........remote at best........

My guess is that you need a new alternator. I had similar problems after installing a new volt. reg. Either that or your belt might not be tight enough.

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1981 300D non-turbo 263,000 mi

I had similar problems after installing a new altenator. In my case the pulley was slipping on the alternator shaft because key on the shaft was cut and worked at low rpm, but with incresed rpm just sliped. Good luck.

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Roman
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87 300SDL 152K
86 420SEL 228K
83 280SL 145K (5 spd)
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Sounds like a bad diode in the alternator.

- Jeff Miller
190DT

I would just unplug and unbolt the alternator. After removal just take it to an auto place that tests alternators for free. They will tell you in a couple of minutes if it's good or bad. Since car is still mobile see if you can get a place to check it while still on car. But remember most those places are in business to make money try for an honest place.

worth checking your battrery cables and grounds if you havent already.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.