LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1527 (HVAC Systems - Automatic) >> Diagnostic Information and Procedures >> Too Cold in Vehicle >> Test Description

Test Description

WARNING: This page is about a different car, the 2004 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.

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

  1. 2:  This step clears the HVAC control module memory and checks for current air temperature actuator diagnostic trouble codes.
  1. 3:  This step checks for A/C compressor clutch always on.
  2. 7:  This test is to insure cooling system is operating normally.
Too Cold 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 the heating is insufficient.
1 Did you perform the HVAC Diagnostic System Check? - Go to Step 2  Go to Diagnostic System Check - HVAC Systems - Automatic 
2 
  1. Recalibrate actuators. Refer to Re-Calibrating Actuators .
  2. Install a scan tool.
  3. Turn ON the ignition, with the engine OFF.
  4. Observe the Diagnostic Trouble Code (DTC) List in Heating and Air Conditioning.
Does the scan tool display any DTC B0361, B0363, B0365, B0367, B0441 or B0446?		 - Go to Diagnostic Trouble Code (DTC) List  Go to Step 3 
3 
IMPORTANT: Ambient air temperature must be above 3°C (38°F).
  1. Start the engine.
  2. Turn OFF the HVAC controls.
Does the A/C compressor operate?		 - Go to HVAC Compressor Clutch Does Not Disengage  Go to Step 4 
4 Place the blower motor switch in each speed position.
Does the blower motor operate in each speed position?		 - Go to Step 5  Go to Blower Motor Inoperative 
5 Does the blower motor provide sufficient air flow? - Go to Step 6  Go to Blower Motor Malfunction 
6
  1. Place the blower motor switch in the maximum speed position.
  2. Place the mode switch in the bi-level position.
  3. Place the outside air switch in the ON position.
  4. Place the recirculation switch in the ON position.
Does the recirculation door operate properly?		 - Go to Step 7  Go to Air Recirculation Malfunction 
7  Inspect the cooling system for the following conditions:
  • A low coolant level
  • A loose or worn accessory drive belt
  • A leaking radiator hose or heater hose
  • A kinked radiator hose or heater hose
  • A missing radiator cap pressure seal
  • A leaking radiator cap

Did you find and correct the condition?		 - Go to Step 20  Go to Step 8 
8
  1. Install a thermometer near the inside air temperature sensor.
  2. With a scan tool, observe the Inside Temp Sensor data parameters in the Heating and Air Conditioning data list.
Does the scan tool indicate that the sensor temperatures are within 3°C (5°F) of the thermometer temperatures?		 - Go to Step 10  Go to Step 9 
9 Inspect for a blocked, malfunctioning, or incorrectly installed inside air temperature sensor. Refer to Inside Air Temperature Sensor Replacement .
Did you find and correct the condition?		 - Go to Step 20  Go to Step 13 
10
  1. Turn the engine OFF.
  2. Install a scan tool.
  3. Cover the sunload sensor.
  4. Start the engine.
  5. Adjust driver side temperature to 22°C (72°F).
  6. With a scan tool, observe the Sun Load Sensor data parameter in the Heating and Air Conditioning data list.
Does the scan tool indicate that the Sunload Sensor parameter is greater than the specified value?		 4.3 V Go to Step 11  Go to Step 15 
11
  1. Uncover the sunload sensor.
  2. Direct a light source at the sunload sensor.
Does the voltage change?		 - Go to Step 12  Go to Step 15 
12 Perform the Heating Performance Diagnostic. Refer to Heating Performance Diagnostic in Heating, Ventilation and Air Conditioning.
Did you find and correct the condition?		 - Go to Step 20  System OK
13 Inspect for poor connections at the harness connector of the inside air temperature sensor. 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 20  Go to Step 14 
14
  1. Turn OFF the ignition.
  2. Test the inside air temperature sensor resistance. Refer to Sensor Resistance Table (Outside Air Temperature - ohms)  or Sensor Resistance Table (Inside Air Temperature - ohms) .
Does the resistance measure near the specified value?		 - Go to Step 16  Go to Step 17 
15 Inspect for poor connections at the harness connector of the sunload sensor. 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 20  Go to Step 18 
16 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 in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 20  Go to Step 19 
17 Replace the inside air temperature sensor. Refer to Inside Air Temperature Sensor Replacement .
Did you complete the replacement?		 - Go to Step 20  -
18 Replace the sunload sensor. Refer to Sun Load Sensor Replacement .
Did you complete the replacement?		 - Go to Step 20  -
19
IMPORTANT: Perform the recalibration procedure for the HVAC control module.
Replace the HVAC control module. Refer to HVAC Control Module Replacement .Did you complete the replacement?		 - Go to Step 20  -
20 Operate the system in order to verify the repair.
Did you correct the condition?		 - System OK Go to Step 3 
scientia non olet · About LEMON Manuals