S 600 (140.057) V12-6.0L (120.982) (1998)
Heater Control Valve: Service and Repair
Removing and Installing Duovalve
Coolant
Drain.
2 electrical connectors
Disconnect.
5 hose straps
Release and pull off hoses.
2 rubber mounts for heating system delivery unit (arrows)
Press off and remove heating system delivery unit
Install
In the reverse sequence, top up coolant and bleed heating system by turning both temperature selectors to the red segments and running the engine
at alternating speeds.
Function check
NOTE: After completing the work erase fault memory in control unit.