Cam Sensors

[AlanW124]

Hello,
I am the second new owner of a 1995 E420 with a M119 engine and new to the MB class. Although the car is beautiful and looks new, is wonderful to drive, it has started having some Check Engine Light issues. The car has 147,000 miles on it. After driving the car 1 week, my CE light came on. Was told by the dealership where I purchase the car, it was the Crankshaft Positioning Sensor(at the flywheel). So, I purchase a new sensor (Hella) installed it. CE light was reset by mechanic from the dealership. About 1 week later, my second CE light comes on. Go back to the dealer, this time, they say, it's the Cam Postioning Sensor, maybe. The mechanic asks about the wiring harness, and I don't know or believe the original owner had this problem fixed. Maybe I should check this first? I have read some threads on the wiring harness, but have not checked it yet. Where is the best place to check for the cracking insulation?
If the insulation is ok, maybe the problem is the cam sensor? I'm assuming the engine has 2 cam sensors. So, my idea is to; buy one sensor and remove and replace until the light goes out, assuming both will not be bad at the same time.
I have the MB bible, but no details about the wiring harness or cam sensors is covered on the M119 engine.
I'm not sure of the locations of the cam sensors. Could someone please tell me the proper location of the sensors? Any help will be appreciated!

Regards, Allan