The digital servo comes with two new sensors that replace the ones in the car. The existing sensor circuit has too many flakey connectors in series with the sensors, the new sensors are hard wired to the servo for a more accurate reading. So the only part of the circuit that remains is the temperature control knob resistor. Also, when I installed my digital unit I cleaned up the vacuum lines that go through the firewall. Since the digital servo controls the pod diaghrams with new vacuum solenoids, I located them inside the car, so the only vacuum line that goes through the firewall is the one that controls the water valve solenoid. Much cleaner looking!

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Richard Wooldridge
'01 ML320
'82 300D 4.3L V6/T700R4 conversion
'82 380SL, '86 560SL engine/trans. installed
'79 450SL, digital servo update
'75 280C