I'm trying to help out a friend with his 1983 380SL. The car won't start; hasn't started in a while. We got a new battery and installed it. As soon as it was installed I noticed the red battery light on the bottom of the gauge cluster was lit with no key in the ignition switch.

My friend was persistent and cranked the engine anyway, it didn't start. I felt the coil and it was very hot. so I took it off and tried it on another car and it was working fine.

Is there common reason(s) why the battery light would stay lit with the car off ?

I am assuming there is a short in the alternator or voltage regulator.

We left the battery terminals off just in case.

Also, is there anyone in the (lower) Westchester County N.Y. area that knows the M116 engine electrics?