J: Manual A/C-Temperature Blend Door Actuator Diagnostics

J1 MANUAL A/C ELECTRONIC DOOR ACTUATOR SYSTEM CHECK

- Start vehicle and run engine until it reaches normal operating temperature.

- Turn on MAX A/C mode.

- Slide temperature control lever to full COOL (left) and check for cool discharge air.

- Slide temperature control lever to full WARM (right) and check for warm discharge air.

- Vary temperature control lever from full WARM to full COOL.

- Did air temperature change?

- Yes
System is fully functional.

- No
Go to J2.

J2 MANUAL A/C ELECTRONIC DOOR ACTUATOR SYSTEM FUSE CHECK

- Check fuse 17 at the fuse panel.

- Is fuse good?

- Yes
Go to J3.

- No
Replace fuse and Go to J1. If fuse blows again, check for shorts to ground in Circuit 247 and SERVICE as needed.

J3 MANUAL A/C ELECTRONIC DOOR ACTUATOR SUPPLY VOLTAGE CHECK






- Disconnect A/C electronic door actuator motor connector located on the evaporator case and accessed through the glove compartment opening.

- Using a test lamp check for battery voltage between Circuit 247 and Circuit 246.

- Did test lamp illuminate?

NOTE: A quick check for the actuator can be done by connecting a replacement actuator and jumper harness to the above connector, then operating system and looking for actuator operation.

- Yes
Go to J4.

- No
Check Circuits 247 and 246 for opens/shorts. Restore vehicle. Retest circuit.

J4 CONTROL HEAD POTENTIOMETER SUPPLY VOLTAGE CHECK











CAUTION: Never jumper Circuit 470 to Circuit 243 (doing so could destroy actuator electronics).

- Reconnect A/C electronic door actuator motor connector at the evaporator case.

- Disconnect heater control connector from the back of the control head.

CAUTION: Never short across Circuits 470 and 243 as this could cause destructive damage.

- Using a voltmeter, check for reference voltage (approximately one to two volts less than battery voltage) between Circuits 470 and 243.

- Is the voltmeter registering one to two volts less than battery voltage?

- Yes
Go to J5.

- No
Check Circuits 470 and 243 for opens/shorts. Restore vehicle. Retest circuit. If wiring to potentiometer is good, then replace the electric actuator assembly.

J5 CONTROL HEAD POTENTIOMETER CHECK

- Disconnect and remove control head potentiometer.

- Using a DVOM, check resistance between terminals 7 and 14.

- With potentiometer at full COOL, resistance should be 3000 ohms.

- With potentiometer at full WARM, resistance should be 15 ohms.

- Is resistance linearly variable from COOL to WARM?

- Yes
Replace electric actuator on EVAP case. Restore vehicle. Retest system.

- No
Replace potentiometer. Restore vehicle. Retest system.