300E 4matic 1991 - no 4 matic light

[justino]

I have a 1991 300E 4matic which has a few faults which may be related, the main one is the 4matic is not operative.

I have noticed that the 4matic light doesn't light up on ignition start up. I also have a low speed ABS fault, and the rear diff locks up at low speed in tight bends, although this only happens after the car has been running for 20 mins or so.

It is possible the faults are linked, eg faulty abs sensor, but this wouldn't explain the 4matic light not lighting up when the ignition is turned on. Through reading the various threads my thoughts are:-

1. Dead 4matic ECU
2. Blown 4matic bulb (does this stop 4matic working?)
3. Faulty OVP - fuses are ok in it.
4. Faulty ABS Sensor

Does the 4matic have a seperate fuse?

Any help would be greatly appreciated.