Hummer H2. Manual - part 1940

DTC B0183 or B0188 

Step

Action

Value

(s)

Yes

No

Schematic Reference: HVAC Schematics 
Connector End View Reference: HVAC Connector End Views

1

Did you perform the HVAC Diagnostic 
System Check?

-

Go to Step 2

Go to Diagnostic 

System Check - 

HVAC Systems - 

Automatic

2

1. Install a scan tool.  

2. Turn ON the ignition, with the engine 

OFF.  

3. With a scan tool, observe the 

appropriate Solar Sensor parameter in 
the Body Control Module data list. 
Refer to one of the following 
parameters: 

z

Left Solar Sensor  

z

Right Solar Sensor  

Does the scan tool indicate that the 
appropriate Solar Sensor parameter is within 
the specified range?

5-250 

Counts

Go to Testing for 

Intermittent 

Conditions and Poor 

Connections in Wiring 

Systems

Go to Step 3

3

1. Turn OFF the ignition.  

2. Disconnect the sunload sensor 

assembly.  

3. Turn ON the ignition, with the engine 

OFF.  

4. With a scan tool, observe the 

appropriate Solar Sensor data 
parameter.  

Does the scan tool indicate that the 
appropriate Solar Sensor parameter is greater 
than the specified value?

250 

Counts

Go to Step 4

Go to Step 5

4

1. Turn OFF the ignition.  

2. Connect a 3 amp fused jumper wire 

between the signal circuit of the 
sunload sensor assembly and the low 
reference circuit of the sunload sensor 
assembly.  

3. Turn ON the ignition, with the engine 

OFF.  

5 

Counts

 

2004 Hummer H2 

2004 HVAC HVAC Systems - Automatic - Hummer H2

  

4. With a scan tool, observe the 

appropriate Solar Sensor parameter.  

Does the scan tool indicate that the 
appropriate Solar Sensor parameter is less 
than the specified value?

Go to Step 8

Go to Step 6

5

Test the solar signal circuit of the sunload 
sensor assembly for a short to ground. Refer 
to Circuit Testing and Wiring Repairs in 
Wiring Systems. 
Did you find and correct the condition?

-

Go to Step 12

Go to Step 9

6

Test the signal circuit of the sunload sensor 
assembly for a short to voltage, a high 
resistance, or an open. Refer to Circuit 
Testing and Wiring Repairs in Wiring 
Systems. 
Did you find and correct the condition?

-

Go to Step 12

Go to Step 7

7

Test the low reference circuit of the sunload 
sensor assembly for a high resistance or an 
open. Refer to Circuit Testing and Wiring 
Repairs in Wiring Systems. 
Did you find and correct the condition?

-

Go to Step 12

Go to Step 9

8

Inspect for poor connections at the harness 
connector of the sunload sensor assembly. 
Refer to Testing for Intermittent 
Conditions and Poor Connections and 
Connector Repairs in Wiring Systems. 
Did you find and correct the condition?

-

Go to Step 12

Go to Step 10

9

Inspect for poor connections at the harness 
connector of the BCM. Refer to Testing for 
Intermittent Conditions and Poor 
Connections and Connector Repairs in 
Wiring Systems. 
Did you find and correct the condition?

-

Go to Step 12

Go to Step 11

10

Replace the sunload sensor assembly. Refer 
to Sun Load Sensor Replacement . 
Did you complete the replacement?

-

Go to Step 12

-

11

Replace the BCM. Refer to Body Control 
Module Replacement in Body Control 
System.Did you complete the replacement?

IMPORTANT:

Perform the set up procedure for the BCM.

-

Go to Step 12

-

1. Use the scan tool in order to clear the 

DTCs.  

 

2004 Hummer H2 

2004 HVAC HVAC Systems - Automatic - Hummer H2

  

DTC B0229, B0414, B0424, OR B3770 

Circuit Description 

The following DTC's are for the HVAC door actuators: 

z

B0229 is for the recirculation actuator.  

z

B0414 is for the left air temperature actuator.  

z

B0424 is for the right air temperature actuator.  

z

B3770 is for the mode actuator.  

The HVAC control module controls the HVAC door actuators to regulate the airflow through the HVAC 
system. Each actuator consists of a stepper motor, a logic circuit, and a potentiometer. The potentiometer inside 
the door actuator allows the module to monitor the current position of the actuator drive shaft. The module 
supplies a 5 volt source voltage to the potentiometer on the 5 volt reference circuit. The module supplies ground 
to the potentiometer through the low reference circuit. The HVAC control module monitors the voltage drop 
across the potentiometer on the door position signal circuit. When the actuator shaft rotates, the voltage on the 
door position signal circuit changes. The module converts the voltage value to a count value where 1 volt is 
approximately equal to 51 counts. 

The HVAC control module calibrates the travel range of the HVAC door actuators when it is initially powered 
by the battery positive voltage circuit. During calibration, the module commands the actuators in each direction 
until door travel is stopped. The module stores the minimum door positions and the maximum door positions of 
each actuator into memory. The total travel range is calculated by subtracting the minimum door position from 
the maximum door position. The door actuators can be calibrated again with a scan tool. 

Conditions for Running the DTC 

z

Battery voltage is 8.7-16.5 volts.  

z

The ignition is ON.  

Conditions for Setting the DTC 

The DTC sets when one of the following conditions are present: 

z

The actual door position value for the actuator is less than 5 counts.  

z

The actual door position value for the actuator is greater than 250 counts.  

z

The actuator fails calibration because the calculated travel range value is too great or too small. 

12

2. Operate the vehicle within the 

Conditions for Running the DTC as 
specified in the supporting text.  

Does the DTC reset?

-

Go to Step 2

System OK

 

2004 Hummer H2 

2004 HVAC HVAC Systems - Automatic - Hummer H2

  

Action Taken When the DTC Sets 

z

If the DTC sets because the actual door position value is out of range, the HVAC control module will 
command the actuator to a default position.  

z

If the DTC sets because the actuator failed a calibration, the HVAC control module will attempt to 
calibrate the motor in the next transition from OFF to RUN mode.  

Conditions for Clearing the DTC 

z

The DTC will become history if the HVAC control module no longer detects the condition that set the 
DTC.  

z

The history DTC will clear after 100 fault free ignition cycles.  

z

The DTC can be cleared with a scan tool.  

Diagnostic Aids 

z

If the condition is not present refer to Testing for Intermittent Conditions and Poor Connections in 
Wiring Systems.  

z

If the DTC sets following a calibration of the door actuator, inspect the door and the actuator for the 
following conditions: 

{

A misaligned actuator  

{

Broken linkages or binding linkages  

{

A broken door or a binding door  

{

An obstruction that prevents the door from operating within the full range of motion  

{

Missing seals to the door  

{

Poor connections at the harness connector of the door actuator  

Test Description 

The numbers below refer to the step numbers on the diagnostic table. 

3: Tests for the proper operation of the circuit in the low voltage range.  

4: Tests for the proper operation of the circuit in the high voltage range. If the jumper fuse opens when 
you perform this test, the circuit is shorted to ground.  

5: Tests for a short to voltage in the 5-volt reference circuit.  

6: Tests for a high resistance or for an open in the low reference circuit.  

DTC B0229, B0414, B0424, or B3770 

Step

Action

Values

Yes

No

Schematic Reference:HVAC Schematics 
Connector End View Reference: HVAC Connector End Views

1

Did you perform the HVAC Diagnostic System 
Check?

-

Go to Diagnostic 

System Check - 

 

2004 Hummer H2 

2004 HVAC HVAC Systems - Automatic - Hummer H2