I don't know about the 450SL, but on my old Chevy this was caused by a bad voltage regulator. It overcharged when the car was running, which damages the battery in the long term. Replaced the regulator and it cleared up.AndrewR said:I'm having an odd problem with my 1974 450SL. With the ignition off, the battery light stays on and then goes off when I turn on the ignition (without starting). Could it be the alternator? The alt. charges fine when running...
I wonder if Andrew every figured out what the problem was? My car just did the same thing and the battery died just sittin there.
I put my hard top back on last Sunday, went for a ride ,I did turn on the heater and fan. Came home and parked it, that night I saw the battery light on, I started it up and the light went off, when I turned the key off the light came back on. Before this the car ran fine.
Then next morning the battery was dead. I disconnected the battery cable and charged the battery,, it took a full charge.
Thats where I am now not sure what to do nextt,,?? Drive it to the local alternator shop and have them check it?
Maybe I crushed the dome light wire putting the top back on,,my trunk light quit working also,, I have to wait for some help pulling the top back off.
WIres are so fine as to appear invisible, but they are there. The wire you refer to is the plugin for the defroster... The power is switched thru a timed relay, so the only power up for a while (length of time, I do not know)...Nor do I have any visible window defroster wires in the back glass. Wonder what the wire that comes out of the hard top is for? I have never connected it before.