Cabin Heater Control Shorted Low (Active) - Mercedes-Benz Sprinter 2003 Manual

HEATING & A/C
Symptom:

CABIN HEATER CONTROL SHORTED LOW (ACTIVE)

CABIN HEATER OR HEATER BOOSTER CONTROL UNIT
CABIN HEATER CONTROL CIRCUIT SHORTED TO GROUND
CABIN HEATER CONTROL CIRCUIT SHORTED TO GROUND CIRCUIT
CABIN HEATER CONTROL CIRCUIT SHORTED TO SENSOR GROUND CIRCUIT
AUTOMATIC TEMPERATURE CONTROL (ATC)
TEST
1 Turn the ignition off.
Disconnect the Cabin Heater or Heater Booster harness connector.
NOTE: All of the following criteria must be met in order to successfully run
the ATC Function Test.
Place the shift lever in Park.
Turn the ignition on.
With the DRBIII , record and erase ATC DTC's.
Start the engine. Allow the engine to reach normal operating temperature.
Set the blower to high speed.
Press the Air Conditioning switch On.
With the DRBIII , verify that the ambient temperature is above 59°F (15°C), the
refrigerant pressure is between 29 and 348 PSI (2 and 24 bar), the evaporator
temperature is above 36.5°F (2.5°C), and the coolant temperature is above 158°F
(70°C).
With the DRBIII in Automatic Temperature Control (ATC), select System Tests and
select ATC Function Test. When the ATC Function Test is complete, proceed as
follows:
With the DRBIII , read the active ATC DTCs.
Does the DRBIII display: CABIN HEATER CONTROL SHORTED LOW?
Yes → Go To 2
→ Replace the Cabin Heater Assembly or the Heater Booster assem-
No
2 Turn the ignition off.
Disconnect the Cabin Heater or Heater Booster harness connector.
Disconnect the Automatic Temperature Control (ATC) C1 harness connector.
Measure the resistance between ground and the Cabin Heater Control circuit.
Is the resistance below 30k ohms?
Yes → Repair the Cabin Heater Control circuit for a short to ground.
→ Go To 3
No
POSSIBLE CAUSES
ACTION
bly in accordance with the Service Information.
Perform BODY VERIFICATION TEST - VER 1.
Perform BODY VERIFICATION TEST - VER 1.
148
APPLICABILITY
All
All