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Mercedes-Benz Sprinter / Dodge Sprinter. Manual - part 507

input signals to control rear blower motor speed and
output air temperature, and to prevent freezing of
the rear evaporator core.

The rear A/C control module cannot be repaired

and, if faulty or damaged, it must be replaced. Refer
to the appropriate wiring information for complete
HVAC wiring diagrams.

REMOVAL

(1) Disconnect and isolate the negative battery

cable.

(2) Remove the air filter from the rear A/C evapo-

rator housing (Refer to 24 - HEATING & AIR CON-
DITIONING/DISTRIBUTION - REAR/AIR FILTER -
REMOVAL).

(3) Reach up into the rear A/C evaporator housing

and disconnect the wire harness connector from the
rear A/C control module (Fig. 6).

(4) Remove the two screws that secure the rear

A/C control module to the rear A/C evaporator hous-
ing and remove the control module.

CONTROLS - REAR

24 - 29

INSTALLATION

(1) Position the rear A/C control module to the

rear A/C evaporator housing.

(2) Install the two screws that secure the rear A/C

control module to the rear A/C evaporator housing.
Tighten the screws to 2 N·m (17 in. lbs.).

(3) Connect the wire harness connector to the rear

A/C control module.

(4) Install the rear air filter (Refer to 24 - HEAT-

ING

AIR

CONDITIONING/DISTRIBUTION

REAR/AIR FILTER - INSTALLATION).

(5) Reconnect the negative battery cable.

A / C HIGH PRESSURE
SWITCH

DESCRIPTION

The rear A/C high pressure switch provides a sig-

nal to the rear A/C control module to control rear A/C
compressor clutch engagement/disengagement and,
control rear A/C condenser cooling fan operation (Fig.
7). The rear A/C control module will disengage the
rear A/C clutch if the rear refrigerant system pres-
sure exceeds approximately 2551 kPa (370 psi).

The rear A/C high pressure switch is mounted on a

fitting located on the inlet tube of the rear A/C con-
denser.

The rear refrigerant system must be discharged

prior to removing the rear A/C high pressure
switch.

OPERATION

The contacts in the rear A/C high pressure switch

open and close causing the rear A/C control module
to turn the rear A/C clutch on and off. This prevents

Fig. 6 Rear A/C Control Module

1 - REAR A/C EVAPORATOR HOUSING
2 - REAR A/C CONTROL MODULE

3 - WIRE HARNESS CONNECTOR
4 - SCREW (2)

Fig. 7 Rear A/C High Pressure Switch

1 - REAR PRESSURE SWITCH
2 - WIRE CONNECTOR

24 - 30

CONTROLS - REAR

rear A/C compressor operation when the rear dis-
charge line pressure approaches high levels, and also
reduces electrical surging from rear A/C clutch
engagement.

The rear A/C high pressure switch controls rear

A/C condenser cooling fan operation by monitoring
the rear discharge line pressure. When the rear dis-
charge pressure rises above approximately 1900 to
2200 kPa (280 to 320 psi) the rear A/C condenser
cooling fan will turn on. The rear condenser cooling
fan will turn off when the rear discharge pressure
drops to approximately 1600 kPa (235 psi).

The rear A/C high pressure switch contacts open

when the rear discharge line pressure rises above
approximately 3100 to 3375 kPa (450 to 490 psi). The
rear A/C high pressure switch contacts close when
the rear discharge line pressure drops to approxi-
mately 1860 to 2275 kPa (270 to 330 psi).

The rear A/C high pressure switch is factory-cali-

brated and cannot be adjusted or repaired and, if
faulty or damaged, it must be replaced. Refer to the
appropriate wiring information for complete HVAC
wiring diagrams.

REMOVAL

WARNING: Refer to the applicable warnings and
cautions for this system before performing the fol-
lowing operation (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING - WARNINGS) and (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMBING -
CAUTIONS). Failure to follow the warnings and cau-
tions could result in possible personal injury or
death.

(1) Disconnect and isolate the negative battery

cable.

(2) Remove the air filter from the rear A/C evapo-

rator housing (Refer to 24 - HEATING & AIR CON-
DITIONING/DISTRIBUTION - REAR/AIR FILTER -
REMOVAL).

(3) Recover the refrigerant from the rear refriger-

ant system (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING - STANDARD PROCEDURE -
REFRIGERANT RECOVERY).

(4) Remove the cover from the rear A/C condenser

housing (Refer to 24 - HEATING & AIR CONDI-
TIONING/DISTRIBUTION

REAR/A/C

CON-

DENSER COVER - REMOVAL).

(5) Disconnect the wire harness connector from the

rear A/C high pressure switch (Fig. 8).

(6) Remove the rear A/C high pressure switch and

install a plug into, or tape over the opened rear dis-
charge line fitting.

INSTALLATION

NOTE: Replacement of the PTFE thread sealing
tape is required anytime the rear A/C high pressure
switch is removed from the rear discharge line. Fail-
ure to replace the sealing tape could result in a rear
refrigerant system leak.

(1) Remove the tape or plug from the rear dis-

charge line fitting.

(2) Install PTFE thread sealing tape onto the rear

A/C high pressure switch and install the switch onto
the rear discharge line. Tightened the A/C high pres-
sure switch to 10 N·m (88 in. lbs.).

(3) Connect the wiring harness connector to the

rear A/C high pressure switch.

(4) Reconnect the negative battery cable.
(5) Evacuate the rear refrigerant system (Refer to

24 - HEATING & AIR CONDITIONING/PLUMBING
- STANDARD PROCEDURE - REFRIGERANT SYS-
TEM EVACUATE).

(6) Charge the rear refrigerant system (Refer to 24

- HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM CHARGE).

(7) Install the rear air filter (Refer to 24 - HEAT-

ING

AIR

CONDITIONING/DISTRIBUTION

REAR/AIR FILTER - INSTALLATION).

(8) Install the cover onto the rear A/C condenser

housing (Refer to 24 - HEATING & AIR CONDI-
TIONING/DISTRIBUTION

REAR/A/C

CON-

DENSER COVER - INSTALLATION).

Fig. 8 Rear A/C High Pressure Switch

1 - REAR A/C CONDENSER
2 - WIRE HARNESS CONNECTOR
3 - REAR A/C HIGH PRESSURE SWITCH
4 - REAR DISCHARGE LINE FITTING

CONTROLS - REAR

24 - 31

A / C LOW PRESSURE SWITCH

DESCRIPTION

The rear A/C low pressure switch provides a signal

to the rear A/C control module to regulate the rear
refrigerant system pressure and control rear A/C
evaporator temperature (Fig. 9). The rear A/C control
module will disengage the rear A/C clutch if the rear
refrigerant system suction line pressure falls below
30 kPa (4.4 psi).

The rear A/C low pressure switch is mounted on a

fitting located on the rear suction line near the left
side of the rear A/C evaporator housing.

The rear refrigerant system must be discharge

prior to removing the rear A/C low pressure switch.

OPERATION

The rear A/C low pressure switch is electrically

connected in series with the rear A/C high pressure
switch, between ground and the rear A/C control
module.

The rear A/C low pressure switch contact opens or

closes the path the ground, signaling the rear A/C
control module to turn the rear A/C clutch on and off.
This regulates the rear refrigerant system pressure
and controls rear A/C evaporator temperature. Con-
trolling the rear evaporator temperature prevents
condensate water on the evaporator fins from freez-
ing and obstructing rear A/C system air flow.

The rear A/C low pressure switch contacts are open

when the rear suction line pressure is approximately
152 kPa (22 psi) or lower. The rear A/C low pressure
switch contacts will close when the rear suction line
pressure rises to approximately 234 to 262 kPa (34 to
38 psi) or above. Lower ambient temperatures, below

approximately -1° C (30° F), will also cause the rear
A/C low pressure switch contacts to open due to the
pressure/temperature relationship of the refrigerant
in the system.

The rear A/C low pressure switch is factory-cali-

brated and cannot be adjusted or repaired and, if
faulty or damaged, it must be replaced. Refer to the
appropriate wiring information for complete HVAC
wiring diagrams.

REMOVAL

(1) Disconnect and isolate the negative battery

cable.

(2) Remove the cover from the rear A/C evaporator

housing (Refer to 24 - HEATING & AIR CONDI-
TIONING/DISTRIBUTION - REAR/A/C EVAPORA-
TOR COVER-REAR - REMOVAL).

(3) Recover the refrigerant from the rear refriger-

ant system (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING - STANDARD PROCEDURE -
REFRIGERANT RECOVERY).

(4) Remove the insulating tape from around the

area of the rear A/C low pressure switch (Fig. 10).

(5) Disconnect the wire harness connector from the

rear A/C low pressure switch.

(6) Remove the rear A/C low pressure switch and

install a plug into, or tape over the opened rear suc-
tion line fitting.

Fig. 9 Rear A/C Low Pressure Switch

1 - REAR PRESSURE SWITCH
2 - WIRE CONNECTOR

24 - 32

CONTROLS - REAR

Content .. 505 506 507 508 ..