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Climate Control Pinpoint Test 6: No Operation In All Temperature Settings

CLIMATE CONTROL PINPOINT TEST 6 CHART - NO OPERATION IN ALL TEMPERATURE SETTINGS

PINPOINT TEST 6 NO OPERATION IN ALL TEMPERATURE SETTINGS
STEP INSPECTION ACTION
1 CHECK THE VOLTAGE TO THE TEMPERATURE BLEND DOOR ACTUATOR MOTOR
  • Key in OFF position.
  • Disconnect: Temperature Blend Door Actuator Motor 0740-107.
  • Key in ON position.
  • Measure the voltage between the temperature blend door actuator motor 0740-107 pin 7 (GY/Y) and ground.
  • Is the voltage greater than 10 volts? 
 Yes Go to step 2.
No Repair circuit (GY/Y). Test the system for normal operation.
2 CHECK THE GROUND TO THE BLEND DOOR ACTUATOR MOTOR
  • Key in OFF position.
  • Measure the resistance between the blend door actuator motor 0740-107 pin 8 (B) and ground.
  • Is the resistance less than 5 ohms? 
 Yes Go to step 3.
No Repair circuit (B). Test the system for normal operation.
3 CHECK THE TEMPERATURE CONTROL POTENTIOMETER TOTAL RESISTANCE
  • Measure the resistance between temperature blend door actuator motor 0740-107 pin 4 (R/W) and 0740-107 pin 6, (R/LG).
  • Is the resistance between 5,000 and 6,000 ohms? 
 Yes Go to step 6.
No If the resistance is less than 5,000 ohms, Go to step 4.
If the resistance is greater than 6,000 ohms, Go to step 5.
4 CHECK CIRCUITS (R/W) AND (R/LG) FOR A SHORT TOGETHER
  • Disconnect: Function Selector Switch Assembly, Front 3-pin connector 0740-104.
  • Measure the resistance between temperature blend door actuator motor 0740-107 pin 4 (R/W) and 0740-107 pin 6, (R/LG).
  • Is the resistance less than 5 ohms? 
 Yes Repair circuits (R/W) and (R/LG) for a short together. Test the system for normal operation.
No INSTALL a new temperature control potentiometer. See HEATER CONTROL UNIT REMOVAL / INSTALLATION . TEST the system for normal operation.
5 CHECK CIRCUITS (R/W) AND (R/LG) FOR AN OPEN
  • Disconnect: Function Selector Switch Assembly, Front 3-pin connector 0740-104.
  • Measure the resistance between temperature blend door actuator motor 0740-107 pin 4 (R/W) and function selector switch assembly, front 3-pin connector 0740-104 pin 3 (R/W), and between temperature blend door actuator motor 0740-107 pin 6 (R/LG) and function selector switch assembly, front 3-pin connector 0740-104 pin 1 (R/LG).
  • Are the resistances less than 5 ohms? 
 Yes Install a new temperature control potentiometer. See HEATER CONTROL UNIT REMOVAL / INSTALLATION . Test the system for normal operation.
No Repair the affected circuit. Test the system for normal operation.
6 CHECK THE TEMPERATURE CONTROL POTENTIOMETER OPERATION
  • Measure the resistance between temperature blend door actuator motor 0740-107 pin 3 (Y/LG) and 0740-107 pin 6 (R/LG) while rotating the temperature control potentiometer from full WARM to full COOL.
  • Does the resistance vary between 250 and 5,500 ohms? 
 Yes Go to step 9.
No Go to step 7.
7 CHECK CIRCUIT (Y/LG) FOR AN OPEN
  • Disconnect: Function Selector Switch Assembly, Front 0740-104.
  • Measure the resistances between actuator motor 0740-107 pin 3 (Y/LG) and function selector switch assembly, front 0740-104 pin 2 (Y/LG).
  • Is the resistance less than 5 ohms? 
 Yes Go to step 8.
No Repair circuit (Y/LG) for an open. Test the system for normal operation.
8 CHECK CIRCUITS (Y/LG) AND (R/LG) FOR A SHORT TOGETHER
  • Measure the resistance between temperature blend door actuator motor 0740-107 pin 3 (Y/LG) and 0740-107 pin 6 (R/LG).
  • Is the resistance less than 5 ohms? 
 Yes Repair circuits (Y/LG) and (R/LG) for a short together. Test the system for normal operation.
No Install a new temperature control potentiometer. See HEATER CONTROL UNIT REMOVAL / INSTALLATION . Test the system for normal operation.
9 CHECK CIRCUITS (Y/LG) AND (R/LG) FOR A SHORT TO GROUND
  • Disconnect: Function Selector Switch Assembly, Front 0740-104.
  • Measure the resistances between temperature blend door actuator motor 0740-107 pin 3 (Y/LG) and ground, and between temperature blend door actuator motor 0740-107 pin 6 (R/LG) and ground.
  • Are the resistances less than 5 ohms? 
 Yes Repair the affected circuit for a short to ground. Test the system for normal operation.
No Go to step 10.
10 CHECK CIRCUITS (Y/LG) AND (R/LG) FOR A SHORT TO VOLTAGE
  • Key in ON position.
  • Measure the voltages between temperature blend door actuator motor 0740-107 pin 6 (R/LG) and ground, and between temperature blend door actuator motor 0740-107 pin 3 (Y/LG) and ground.
  • Is the voltage greater than 10 volts? 
 Yes Repair the affected circuit for a short to power. Test the system for normal operation.
No Go to step 11.
11 CHECK FOR A BINDING, STUCK OR BROKEN BLEND DOOR
  • Key in OFF position.
  • Remove the actuator motor. See BLEND DOOR ACTUATOR REMOVAL / INSTALLATION
  • Inspect for a binding, stuck or broken blend door or linkage.
  • Is there a binding, stuck or broken blend door or linkage condition? 
 Yes Repair the blend door/linkage. Test the system for normal operation.
No Install a new temperature blend door actuator motor. See BLEND DOOR ACTUATOR REMOVAL / INSTALLATION . Test the system for normal operation.
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