83' Euro 500sl.

I've searched on ABS but not located quite these symptoms.

When I depress the brake pedal firmly the ABS light comes on, I can apply less pressure to the pedal and the light will flicker.
If I do this same test with the car not running but the key on the ABS light still comes on but it is either on or off no flicker.

I would think this rules out the sensor, correct?
A short maybe? How would I diagnose.
I have the Service CD, doesn't say much about ABS but, then again it doesn't reference the euro cars.

I wasn't even sure this car had ABS, if so it must be rear only because I have locked up the front wheels before.
I've never felt a pulse in the pedal.


Any help would be greatly appreciated.

Thanks

Marc

__________________
1983' SL500 euro