2006 MERCEDES-BENZ SPRINTER ignition

TEST ACTION APPLICABILITY
3 Turn the ignition off.
Remove the A/C Auxiliary Fan Relay from the relay center.
Disconnect the Automatic Temperature Control (ATC) C1 harness connector.
Measure the resistance between the A/C Auxiliary Fan Relay High Side Control
circuit and the Ground circuit in the Automatic Temperature Control (ATC) C1
harness connector.
Is the resistance below 10K ohms?All
Ye s!Repair the A/C Auxiliary Fan Relay High Side Control circuit for
a short to the Ground circuit.
Perform BODY VERIFICATION TEST - VER 1.
No!Go To 4
4 Turn the ignition off.
Remove the A/C Auxiliary Fan Relay from the relay center.
Disconnect the Automatic Temperature Control (ATC) C1 harness connector.
Measure the resistance between the A/C Auxiliary Fan Relay High Side Control
circuit and the Sensor Ground circuit in the Automatic Temperature Control (ATC)
C1 harness connector.
Is the resistance below 10K ohms?All
Ye s!Repair the A/C Auxiliary Fan Relay High Side Control circuit for
a short to the Sensor Ground circuit.
Perform BODY VERIFICATION TEST - VER 1.
No!Replace the Automatic Temperature Control (ATC) in accordance
with the Service Information.
Perform BODY VERIFICATION TEST - VER 1.
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HEATING & A/C
AUX FAN RELAY CONTROL SHORTED LOW (ACTIVE) ÐContinued

Symptom:
BLOWER STAGE 1 HIGH OR OPEN (ACTIVE)
POSSIBLE CAUSES
BLOWER MOTOR
BLOWER MOTOR DRIVER CIRCUIT(S) SHORTED TO VOLTAGE
BLOWER MOTOR DRIVER CIRCUIT(S) OPEN
BLOWER MOTOR RESISTOR BLOCK
AUTOMATIC TEMPERATURE CONTROL (ATC)
TEST ACTION APPLICABILITY
1 Turn the ignition off.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Blower Motor harness connector.
Connect a fused jumper wire between Battery (+) and Blower Motor cavity 1.
Connect a jumper wire between ground and Blower Motor cavity 2.
Does the Blower Motor run at full speed?All
Ye s!Go To 2
No!Replace the Blower Motor in accordance with the Service Infor-
mation.
Perform BODY VERIFICATION TEST - VER 1.
2 Turn the ignition off.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Blower Motor Resistor Block harness connector.
Disconnect the Blower Motor harness connector.
Disconnect the Automatic Temperature Control (ATC) C2 harness connector.
Turn the ignition on.
Measure the voltage of each of the Blower Motor Driver circuits (Low, M1, M2, High).
Is the voltage above 0.2 volts on any of the circuits?All
Ye s!Repair each circuit with voltage above 0.2 volts for a short to
voltage.
Perform BODY VERIFICATION TEST - VER 1.
No!Go To 3
3 Turn the ignition off.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Automatic Temperature Control (ATC) C2 harness connector.
Disconnect the Blower Motor Resistor Block harness connector.
Disconnect the Blower Motor harness connector.
Measure the resistance of the Blower Motor Driver circuits (Low, M1, M2, High)
between the Automatic Temperature Control (ATC) C2 harness connector and the
Blower Motor Resistor Block harness connector.
Measure the resistance of the Blower Motor High Driver circuit between the
Automatic Temperature Control (ATC) C2 harness connector and the Blower Motor
harness connector.
Is the resistance below 5.0 ohms on each of the circuits?All
Ye s!Go To 4
No!Repair each circuit with a resistance above 5.0 ohms for an open.
Perform BODY VERIFICATION TEST - VER 1.
144
HEATING & A/C

TEST ACTION APPLICABILITY
4 Turn the ignition off.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Blower Motor Resistor Block harness connector.
Measure the resistance between Blower Motor Resistor Block cavity 2 and cavity 1.
The approximate resistance should be 1.4 ohms.
Measure the resistance between Blower Motor Resistor Block cavity 2 and cavity 3.
The approximate resistance should be 0.8 ohms.
Measure the resistance between Blower Motor Resistor Block cavity 2 and cavity 4.
The approximate resistance should be 1.6 ohms.
Is the resistance as specified for each circuit?All
Ye s!Replace the Automatic Temperature Control (ATC) in accordance
with the Service Information.
Perform BODY VERIFICATION TEST - VER 1.
No!Replace the Blower Motor Resistor Block in accordance with the
Service Information.
Perform BODY VERIFICATION TEST - VER 1.
145
HEATING & A/C
BLOWER STAGE 1 HIGH OR OPEN (ACTIVE) ÐContinued

Symptom:
BLOWER STAGE 1 SHORTED LOW (ACTIVE)
POSSIBLE CAUSES
BLOWER MOTOR FUSE
BLOWER MOTOR
BLOWER MOTOR DRIVER CIRCUIT(S) SHORTED TO GROUND
FUSED B+ CIRCUIT SHORTED TO GROUND
BLOWER MOTOR RESISTOR BLOCK
AUTOMATIC TEMPERATURE CONTROL (ATC)
TEST ACTION APPLICABILITY
1 Turn the ignition off.
Remove and inspect the Blower Motor Fuse, and replace it if necessary.
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 DRBIIIt, 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 DRBIIIt, verify that the ambient temperature is above 59ÉF (15ÉC), the
refrigerant pressure is between 29 and 348 PSI (2 and 24 bar), the evaporator
temperature is above 36.5ÉF (2.5ÉC), and the coolant temperature is above 158ÉF
(70ÉC).
With the DRBIIItin Automatic Temperature Control (ATC), select System Tests and
select ATC Function Test. When the ATC Function Test is complete, proceed as
follows:
With the DRBIIIt, read the active ATC DTCs.
Does the DRBIIItdisplay: BLOWER STAGE ONE SHORTED LOW?All
Ye s!Go To 2
No!Refer to the wiring diagrams located in the service information to
help isolate a possible intermittent short to ground condition.
Perform BODY VERIFICATION TEST - VER 1.
2 Turn the ignition off.
Disconnect the Blower Motor harness connector.
Connect a fused jumper wire between Battery (+) and Blower Motor cavity 1.
Connect a jumper wire between ground and Blower Motor cavity 2.
Does the Blower Motor run at full speed?All
Ye s!Go To 3
No!Replace the Blower Motor in accordance with the Service Infor-
mation. Remove and inspect the Blower Motor Fuse, and replace
it if necessary.
Perform BODY VERIFICATION TEST - VER 1.
146
HEATING & A/C

TEST ACTION APPLICABILITY
3 Turn the ignition off.
Disconnect the Blower Motor Resistor harness connector.
Disconnect the Blower Motor harness connector.
Disconnect the Automatic Temperature Control (ATC) C2 harness connector.
Measure the resistance between ground and each of the Blower Motor Driver circuits
(Low, M1, M2, High).
Is the resistance below 10k ohms on any of the circuits?All
Ye s!Repair each circuit with a resistance below 10k ohms for a short
to ground. Remove and inspect the Blower Motor Fuse, and
replace it if necessary.
Perform BODY VERIFICATION TEST - VER 1.
No!Go To 4
4 Turn the ignition off.
Remove the Blower Motor Fuse.
Disconnect the Automatic Temperature Control (ATC) C2 harness connector.
Measure the resistance between ground and the Fused B+ circuit.
Is the resistance below 10k ohms?All
Ye s!Repair the Fused B+ circuit for a short to Ground. Remove and
inspect the Blower Motor Fuse, and replace it if necessary.
Perform BODY VERIFICATION TEST - VER 1.
No!Go To 5
5 Turn the ignition off.
Disconnect the Blower Motor Resistor Block harness connector.
Measure the resistance between Blower Motor Resistor Block cavity 2 and cavity 1.
The approximate resistance should be 1.4 ohms.
Measure the resistance between Blower Motor Resistor Block cavity 2 and cavity 3.
The approximate resistance should be 0.8 ohms.
Measure the resistance between Blower Motor Resistor Block cavity 2 and cavity 4.
The approximate resistance should be 1.6 ohms.
Is the resistance as specified for each circuit?All
Ye s!Replace the Automatic Temperature Control (ATC) in accordance
with the Service Information. Remove and inspect the Blower
Motor Fuse, and replace it if necessary.
Perform BODY VERIFICATION TEST - VER 1.
No!Replace the Blower Motor Resistor Block in accordance with the
Service Information. Remove and inspect the Blower Motor Fuse,
and replace it if necessary.
Perform BODY VERIFICATION TEST - VER 1.
147
HEATING & A/C
BLOWER STAGE 1 SHORTED LOW (ACTIVE) ÐContinued

Symptom:
CABIN HEATER CONTROL HIGH OR OPEN (ACTIVE)
POSSIBLE CAUSES
CABIN HEATER OR HEATER BOOSTER CONTROL UNIT
CABIN HEATER CONTROL CIRCUIT SHORTED TO VOLTAGE
AUTOMATIC TEMPERATURE CONTROL (ATC)
CABIN HEATER CONTROL CIRCUIT OPEN
AUTOMATIC TEMPERATURE CONTROL (ATC)
TEST ACTION APPLICABILITY
1 Turn the ignition on.
Verify that the Cabin Heater or Heater Booster is switched off.
Turn the ignition off.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Cabin Heater or Heater Booster harness connector.
Connect a 12-volt test light between the Cabin Heater Control circuit and ground.
Turn the ignition on. The test light should operate as follows:
With the Cabin Heater or Heater Booster switched off, the test light should not
illuminate.
Press the Cabin Heater or Heater Booster switch on. The test light should illuminate
brightly.
Does the test light function as specified?All
Yes, Light Only Illuminates w/Switch On
Replace the Cabin Heater Assembly or the Heater Booster Assem-
bly in accordance with the Service Information.
Perform BODY VERIFICATION TEST - VER 1.
No, Light Illuminates w/Switch Off
Go To 2
No, Light Will Not Illuminate
Go To 3
2 Turn the ignition off.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Cabin Heater or Heater Booster harness connector.
Disconnect the Automatic Temperature Control (ATC) C1 harness connector.
Turn the ignition on.
Measure the voltage of the Cabin Heater Control circuit.
Is the voltage above 0.2 volts?All
Ye s!Repair the Cabin Heater Control circuit for a short to voltage.
Perform BODY VERIFICATION TEST - VER 1.
No!Replace the Automatic Temperature Control (ATC) in accordance
with the Service Information.
Perform BODY VERIFICATION TEST - VER 1.
148
HEATING & A/C

TEST ACTION APPLICABILITY
3 Turn the ignition off.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Automatic Temperature Control (ATC) C1 harness connector.
Disconnect the Cabin Heater or Heater Booster harness connector.
Measure the resistance of the Cabin Heater Control circuit between the Automatic
Temperature Control (ATC) C1 harness connector and the Cabin Heater or Heater
Booster harness connector (as applicable).
Is the resistance below 5.0 ohms?All
Ye s!Replace the Automatic Temperature Control (ATC) in accordance
with the Service Information.
Perform BODY VERIFICATION TEST - VER 1.
No!Repair the Cabin Heater Control circuit for an open.
Perform BODY VERIFICATION TEST - VER 1.
149
HEATING & A/C
CABIN HEATER CONTROL HIGH OR OPEN (ACTIVE) ÐContinued

Symptom:
CABIN HEATER CONTROL SHORTED LOW (ACTIVE)
POSSIBLE CAUSES
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 ACTION APPLICABILITY
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 DRBIIIt, 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 DRBIIIt, verify that the ambient temperature is above 59ÉF (15ÉC), the
refrigerant pressure is between 29 and 348 PSI (2 and 24 bar), the evaporator
temperature is above 36.5ÉF (2.5ÉC), and the coolant temperature is above 158ÉF
(70ÉC).
With the DRBIIItin Automatic Temperature Control (ATC), select System Tests and
select ATC Function Test. When the ATC Function Test is complete, proceed as
follows:
With the DRBIIIt, read the active ATC DTCs.
Does the DRBIIItdisplay: CABIN HEATER CONTROL SHORTED LOW?All
Ye s!Go To 2
No!Replace the Cabin Heater Assembly or the Heater Booster assem-
bly in accordance with the Service Information.
Perform BODY VERIFICATION TEST - VER 1.
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?All
Ye s!Repair the Cabin Heater Control circuit for a short to ground.
Perform BODY VERIFICATION TEST - VER 1.
No!Go To 3
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HEATING & A/C