Neal -

Battery at rest should read about 12.7V. With engine on and idling, normal load, it should read about 13.75V or so. Try increasing the load (lights, heater) and check V at idle and also at 1500 RPM or so. See what the values are. If they stay high (at or around 13.5V) you know your alternator is working.

Also check the alternator brushes to see if they are worn and may require replacment. Your 13.0V at idle reading seems very low.

C.

__________________
Chris
2007 E550 4Matic - 61,000 Km - Iridium Silver, black leather, Sport package, Premium 2 package
2007 GL450 4Matic - 62,000 Km - Obsidian Black Metallic, black leather, all options
1998 E430 - sold
1989 300E - 333,000 Km - sold
1977 280E - sold
1971 250 - retired

"And a frign hat. They gave me a hat at the annual benefits meeting. I said. how does this benefit me. I dont have anything from the company.. So they gave me a hat." - TheDon