Pinpoint Test G: HVAC Functions Verification

WARNING: This page is about a different car, the 2008 Mercury Sable, 2008 Ford Taurus X, and 2008 Ford Taurus. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Diagnose any HVAC module DTCs before carrying out the following pinpoint test.

NOTE: Some PCM DTCs may inhibit A/C operation. If any PCM DTCs are retrieved, diagnose those first. Refer to PCM DTC Table .

G1 CHECK THE BLOWER MOTOR OPERATION
- Key in ON position.
- Select PANEL mode.
- Observe blower motor operation and select each blower motor speed.
- Does the blower motor operate in all selections and change speed in each?
1. YES : Go to G2.
2. NO : Electronic Manual Temperature Control (EMTC) systems, if the blower motor does not operate in any setting, go to Pinpoint Test O .
  Dual Automatic Temperature Control (DATC) systems, if the blower motor does not operate in any setting, go to Pinpoint Test Q .
  
  EMTC systems, if the blower motor does not properly change speeds or shut OFF, go to Pinpoint Test P .
  
  DATC systems, if the blower motor does not properly change speeds or shut OFF, go to Pinpoint Test R .
G2 CHECK AIRFLOW OPERATION
- Select the highest blower motor setting.
- While observing the airflow, select each of the airflow positions (PANEL, PANEL/FLOOR, FLOOR, FLOOR/DEFROST, DEFROST).
- Is the airflow directed to the proper outlets?
1. YES : Go to G3.
2. NO : Go to Pinpoint Test I .
G3 VERIFY TEMPERATURE CONTROL OPERATION
- Start the vehicle and allow it to reach normal operating temperature.
- With the A/C OFF, select PANEL mode.
- Change the temperature setting from the coldest to the warmest and back to the coldest.
- Does the temperature change between very warm to cool?
1. YES : Go to G4.
2. NO : If the temperature does not get very warm, go to Pinpoint Test J .
  If the temperature does not change at all, go to Pinpoint Test N .
G4 VERIFY THE A/C CLUTCH DOES NOT ENGAGE WITH A/C OFF
- With the A/C OFF, select PANEL mode.
- Select the coldest temperature setting.
- Is the outlet temperature close to ambient temperature?
1. YES : Go to G5.
2. NO : If the temperature is warmer than ambient temperature, go to Pinpoint Test N and diagnose for inoperative blend door.
  If the outlet temperature is significantly colder than ambient temperature and the A/C compressor clutch cycles normally, go to Pinpoint Test M .
  
  If the outlet temperature is significantly colder than ambient temperature and the A/C compressor clutch does not cycle, go to Pinpoint Test L .
G5 VERIFY A/C CLUTCH ENGAGEMENT IN THE A/C MODE
- Make sure the ambient air temperature is above 2°C (35°F).
- Select PANEL mode.
- Press the A/C button (indicator ON).
- Does the A/C clutch engage when the PANEL and A/C buttons (indicator ON) are pressed?
1. YES : Go to G6.
2. NO : Go to Pinpoint Test K .
G6 CHECK THE RECIRC OPERATION
- Press the RECIRC button (indicator OFF).
- Select PANEL mode.
- Select the highest blower motor setting.
- Observe airflow noise.
- Press the RECIRC button (indicator ON).
- Does the airflow noise increase when the RECIRC mode is selected (indicator ON)?
1. YES : If the vehicle is not equipped with auxiliary climate control, the system is operating normally.
  If the vehicle is equipped with auxiliary climate control, go to G7.
2. NO : Go to Pinpoint Test I .
G7 CHECK THE AUXILIARY BLOWER MOTOR OPERATION
- Using the front and rear auxiliary blower motor controls, observe blower motor operation and select each auxiliary blower motor speed.
- Does the auxiliary blower motor operate in all selections and change speed in each?
1. YES : Go to G8.
2. NO : If the auxiliary blower motor does not operate in any setting, go to Pinpoint Test S .
  If the auxiliary blower motor does not properly change speeds or shut OFF using both the front and rear auxiliary controls, go to Pinpoint Test T .
  
  If the auxiliary blower motor does not properly change speeds or shut OFF using both the rear auxiliary controls only, go to Pinpoint Test W .
G8 VERIFY AUXILIARY TEMPERATURE/MODE OPERATION
- Select the highest auxiliary blower motor setting.
- Using the front and rear auxiliary controls, change the temperature/mode setting from the coldest to the warmest/floor and back to the coldest/overhead.
- Does the temperature change between very warm to cool and auxiliary airflow to the floor when warm is selected and headliner when cool is selected?
1. YES : The system is operating normally.
2. NO : If the auxiliary temperature control is inoperative/does not operate correctly from both the front and rear auxiliary controls, go to Pinpoint Test U .
  If the auxiliary temperature control is inoperative/does not operate correctly from the rear auxiliary controls only, go to Pinpoint Test W .
  
  If the auxiliary temperature control is inoperative/does not operate correctly from the front auxiliary controls only, CARRY OUT the HVAC Module Cold Boot Process. If the condition returns, INSTALL a new HVAC module. REFER To CLIMATE CONTROL article. TEST the system for normal operation.
  
  If the auxiliary panel/floor control is inoperative/does not operate correctly from both the front and rear auxiliary controls, go to Pinpoint Test V .
  
  If the auxiliary panel/floor control is inoperative/does not operate correctly from the rear auxiliary controls only, go to Pinpoint Test W .
  
  If the auxiliary panel/floor control is inoperative/does not operate correctly from the front auxiliary controls only, CARRY OUT the HVAC Module Cold Boot Process. If the condition returns, INSTALL a new HVAC module. REFER to CLIMATE CONTROL article. TEST the system for normal operation.