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Home >> Isuzu >> 2007 >> i-290 LS, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 13 (HVAC System - Automatic) >> Diagnostic Information and Procedures >> Too Hot in Vehicle >> Test Description

Test Description

WARNING: This page is about a different car, the 2007 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.

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

  1. 2:  This test resets the HVAC control module and checks for current air temperature actuator DTC.
  2. 7:  Ambient air temperature must be above 3°C (38°F) in order for this A/C Compressor test to be run.
Too Hot in Vehicle

Step Action Values Yes No
Schematic Reference: HVAC Schematics 
Connector End View Reference: HVAC Connector End Views 
DEFINITION: The temperature cannot be adjusted, or cooling is insufficient during the A/C operation.
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle
2 
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the current DTC list for the HVAC Module.
Does the scan tool display DTC B0408, B0409, B0419 or B0423?		 - Go to Diagnostic Trouble Code (DTC) List - Vehicle Go to Step 3 
3 Place the blower motor switch in each speed position.
Does the blower motor operate in any speed position?		 - Go to Step 4  Go to Blower Motor Malfunction 
4 Does the blower motor operate in each speed position? - Go to Step 5  Go to Blower Motor Malfunction 
5
  1. Place the blower motor switch in the maximum speed position.
  2. Place the mode controls in the BI-LEVEL position.
  3. Alternately, place the recirculation switch in the outside air and recirculation positions.
Does the recirculation door move from the recirculation position to the ambient air position?		 - Go to Step 6  Go to Air Delivery Improper 
6 Place the passenger temperature in the OFF position.
Does the Too Hot in Vehicle concern occur when A/C cooling desired?		 - Go to Step 7  Go to Step 9 
7 
IMPORTANT: Ambient air temperature must be above 3°C (38°F).
  1. Cover the sunload sensor.
  2. Start the engine.
  3. Open all panel outlets in order to allow maximum air flow.
  4. Place the air temperature switch to the coldest position.
  5. Place the mode switch in the VENT position.
  6. Place the blower motor switch in the maximum speed position.
  7. Ensure that the vent indicator is not illuminated.
Does the A/C compressor operate?		 - Go to Step 8  Go to HVAC Compressor Clutch Does Not Engage 
8 Perform the A/C system performance test. Refer to Air Conditioning (A/C) System Performance Test .
Did you find and correct the condition?		 - Go to Step 26  Go to Step 9 
9 Inspect the upper left, upper right, lower left, and lower right air temperature sensors for the following conditions:
  • An obstruction to the airflow
  • A damaged or a missing seal to the sensor
  • Misaligned air ducts
  • A misaligned sensor

Did you find and correct the condition?		 - Go to Step 26  Go to Step 10 
10
  1. Turn ON the ignition, with the engine OFF.
  2. Inspect for airflow through the inside air temperature assembly by placing a 5 cm (2 in) square piece of paper over the sensor air inlet.
Does the paper stay in place?		 - Go to Step 11  Go to Step 14 
11
  1. Install a thermometer near the upper left, upper right, lower left, and lower right air sensors and the inside air temperature assembly.
  2. With a scan tool, observe the Inside Air Temp. data parameter in the Instrument Panel Module Data list.
Does the scan tool indicate that the sensor temperatures are within the specifications at the thermometer temperatures?		 -3 to +3°C (-5 to +5°F) Go to Step 12  Go to Step 17 
12
  1. Turn the engine OFF.
  2. Install a scan tool.
  3. Cover the sunload sensor.
  4. Start the engine.
  5. Place the driver side temperature at 22°C (72°F).
  6. With a scan tool, observe the Solar Sensor data parameter in the Instrument Panel Module data list.
Does the scan tool indicate that the solar sensor parameter is greater than the specified value?		 224 Counts Go to Step 13  Go to Step 19 
13
  1. Uncover the sunload sensor.
  2. Direct a light source at the sunload sensor.
Do the counts change?		 - System OK Go to Step 19 
14
  1. Disconnect inside air temperature assembly.
  2. Turn ON the ignition, with the engine OFF.
  3. Connect a test lamp between the ignition 3 circuit of the inside air temperature assembly and the inside air temperature assembly control circuit of the inside air temperature assembly.
Does the test lamp illuminate?		 - Go to Step 18  Go to Step 15 
15 Test the ignition 3 voltage circuit of the inside air temperature assembly for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?		 - Go to Step 26  Go to Step 16 
16 Test the inside air temperature assembly control circuit of the inside air temperature assembly for the following conditions:
Did you find and correct the condition?		 - Go to Step 26  Go to Step 20 
17 Test the suspect temperature sensor resistance. Refer to Sensor Resistance Table  table.
Does the resistance measure near the Sensor Resistance Table?		 - Go to Step 21  Go to Step 18 
18 Inspect for poor connections at the harness connector of the suspect air temperature sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?		 - Go to Step 26  Go to Step 22 
19 Inspect for poor connections at the harness connector of the sunload sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?		 - Go to Step 26  Go to Step 23 
20 Inspect for poor connections at the harness connector of the HVAC module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?		 - Go to Step 26  Go to Step 24 
21 Inspect for poor connections at the harness connector of the HVAC control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?		 - Go to Step 26  Go to Step 25 
22 Replace the appropriate temperature sensor. Refer to Inside Air Temperature Sensor Assembly Replacement .
Did you complete the replacement?		 - Go to Step 26  -
23 Replace the sunload sensor. Refer to Sun Load Sensor Replacement .
Did you complete the replacement?		 - Go to Step 26  -
24 Replace the HVAC module. Refer to Control Module References for replacement, setup, and programming.
Did you complete the replacement?		 - Go to Step 26  -
25 Replace the HVAC control module. Refer to Control Module References for replacement, setup, and programming.
Did you complete the replacement?		 - Go to Step 26  -
26 Operate the system in order to verify the repair.
Did you correct the condition?		 - System OK Go to Step 3 
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