Removal and installation of the heating system delivery unit - ra83001400115x(0115)

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Automatic heater control - A. Duo valve, B. Circulation pump Model 140

Operation No. of Job Texts and Work Units, Standard Texts and Flat Rates:

A. Removing and installing duo valve

Fig 1: Identifying Duo Valve Components

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Coolant	Drain (20-010).
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	Refer to diagnosis manual.
	After completing the work: Erase fault memory in control unit (Diagnosis Manual - Climate Control).

B. Removing and installing circulation pump

Fig 2: Identifying Circulation Pump Components

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Pressure in cooling system	Release by turning cooler cap to detent "1" and sealing it again.
2-pole connector	Pull off.
4 screws (arrows)	Unscrew and remove.
Circulation pump (A31m1)	Remove.
Install	In the reverse sequence.
Check	Function of system, run engine at idle and turn temperature selectors to red segments. It must be possible to feel the circulation pump running.
	After completing the work: Erase fault memory in control unit (Diagnosis Manual - Climate Control).