Removal and installation of heater unit - ra83001400100x(0100)

WARNING: This page does not describe the selected car, but rather 42 other vehicles, including the 1999 Mercedes-Benz S600, 1999 Mercedes-Benz S500, 1999 Mercedes-Benz S420, 1999 Mercedes-Benz S320, and 1999 Mercedes-Benz CL600. However, it is still accessible from the selected car via links, so may be relevant.

Model 140 with automatic heater control

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

Fig 1: Identifying Heater Unit Components (1 Of 2)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Battery	Disconnect negative terminal.
Coolant	Drain.
Wiper system	Remove (REMOVAL AND INSTALLATION OF WIPER SYSTEM ).
Water collector (Fig 1)	Remove (Removal and installation of the air collector unit and water collector ).
Hoses at heat exchanger	Disconnect and seal off openings (parts kit 140 830 01 27).
Pre-resistor group (Fig 1, A32r1, r2, r3)	Remove, unscrew 1 nut (arrow) and pull off pre-resistor group (plug connection).
3 nuts (Fig 1, no. 91) on firewall	Unscrew.
Electrical connectors at blower carrier	Disconnect.

Fig 2: Identifying Heater Unit Components (2 Of 2)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Dashboard	Remove (REMOVAL AND INSTALLATION OF THE INSTRUMENT PANEL ).
Center console	Remove (REMOVAL AND INSTALLATION OF THE CENTER CONSOLE ).
Insulation mat above heater unit	Remove.
Floor carpets on driver's side	Take out.
Rear footwell air ducts	Remove.
Air duct for rear air outlet	Remove (1 nut).
Cable for rear air outlet	Unclip.
Airbag/belt tensioner control unit	Remove (REMOVAL AND INSTALLATION OF AIRBAG AND SEAT BELT TENSIONER CONTROL UNIT ).
Ignition starter switch	Remove (46-645).
Cross brace in front of heater unit	Remove (1 nut and 3 screws).
Stiffening tubes left and right of carrier	Remove
	Left	3 screws
		2 nuts
	Right	1 screw
		1 nut
Bracket (Fig 2, no. 93)	Remove.
3 nuts (Fig 2, Fig 2 and Fig 2, no. 92)	Unscrew.
Left outside bracket on heater unit	Remove (3 nuts).
Right outside bracket on heater unit	Remove (4 nuts).
Bearing tube, right	Remove (3 screws and 5 nuts), unclip switch-over valve connector block (Removal and installation of the switchover valve connector block (Y13/2) ).
2 nuts (Fig 2, no. 92) between defroster outlets	Unscrew.
Air ducts to left and right side outlets	Remove.
Connector (Fig 2, X49/2)	Disconnect, unscrew bracket.
Cable harness for blower	Pull out of heater unit together with rubber grommet.
Connector, vacuum line to main air flap(Fig 2)	Disconnect.
Vacuum line at vacuum valve block (gray-green, connection 5)	Pull off.
Heater unit	Pull out towards the rear.
Heater unit	Install in the reverse sequence.
Coolant	Top up and check cooling system for leaks (TESTING COOLING SYSTEM FOR LEAKS ).
Check	Function of system.
	Erase fault memory in control unit (N18) (Diagnosis Manual - Climate Control).