electrical problem
 

1982 300sd

the battery on my car keeps getting drained overnight. i tested at each fuse while the key was OUT. all fuse/circuits pull nothing except fuse/circuit 13 "clock, diagnostic, warning, radio" is pulling 0.8amps when the car is just sitting. is this about the regular amount or is that way too much for just the clock to be running?

thanks.
-philip

My estimate is that 800ma is probably about 100 times too much, assuming key off.

thanks man. this gives me a good starting place for solving the problem.

Disconnect one of the battery terminals when you put it up for the night. If the battery is still dead in the morning than the batter is no good.
How many amps will the clock in the instrument cluster pull?

The few accessories that draw power, including the clock, will typically amount to 50-60ma in most older vehicles.

I have the exact same problem with my 84 300SD
 

I came here to ask what might be the problem and found this thread instead. I have asked around on other sites, one mechanic said to first check the vacuum on the power door locks which is in the trunk by the wheel well.

I haven't found the problem yet. Please let me know if you find out anything.

Hawkdevil,
I would think there would be a problem with the doors unlocking if the pump in the trunk had a run-on problem.

PGringo,
Isn't the electric antenna on that circuit? If so, try unplugging it and see if you have any luck. I have read here of someone else having a problem in that area, causing discharge problems.

Trunk or glove compartment lights remaining on catch a few fellows. If the drain remains with all the fuses pulled one at a time the alternator might have a leaky diode. Best to put an ampmeter into the circuit for testing. Install it between the battery post and cable. . Also some aftermarket radios are not installed correctly. This is the first place I usually go.