E: EATC HEATER BLOWER MOTOR DOES NOT OPERATE AT LOWER SPEEDS

PINPOINT TEST E: EATC HEATER BLOWER MOTOR DOES NOT OPERATE AT LOWER SPEEDS

E1 CHECK BLOWER MOTOR LO SPEED OPERATION

- Start engine, select MAX A/C and position the blower thumbwheel to LO. The blower motor should operate at low speed.
- Slowly rotate the blower thumbwheel to HI. The A/C blower motor speed should increase until high blower speed is obtained.

- Does the A/C blower speed increase to high speed?

- Yes
Perform Pinpoint Test Step A1.

- No
Go to E2.

E2 CHECK VOLTAGE BETWEEN BLOWER MOTOR SPEED CONTROL PINS 2 AND 5

- Turn ignition switch to off.
- Start engine, select MAX A/C and rotate the blower thumbwheel to LO. Check voltage between Pins 2 and 5 of the blower motor speed controller harness connector. Voltage reading should be between 1 and 2 volts.

- Is the voltage measurement between 1 and 2 volts?

- Yes
Replace the A/C blower motor speed control. Restore vehicle. Retest system.

- No
Go to E3.

E3 VERIFY VOLTAGE MEASUREMENT

- Verify the voltage reading obtained in Step E2.

- Does the voltage measure zero volts?

- Yes
Go to E4.

- No
Retest. Go to E1.

E4 VOLTAGE CHECK AT EATC PIN 7

- Start engine, select MAX A/C and rotate the blower thumbwheel to LO.
- Check voltage between Pin 7 of EATC control assembly and ground. Should indicate 1 to 2 volts.

- Is the voltage measurement between 1 and 2 volts?

- Yes
Service Circuit 756 (R/PK) for Town Car or Circuit 752 (Y/R) for Crown Victoria, Grand Marquis between Pin 7 of EATC control assembly and Pin 2 of A/C blower motor speed controller for open. Restore vehicle. Retest system.

- No
Go to E5.

E5 ZERO VOLTAGE CHECK AT PIN 7

- Verify the voltage recorded in Step E4.

- Does the voltage between Pin 7 and ground measure zero volts?

- Yes
Replace the EATC control assembly. Restore vehicle. Retest system.

- No
Retest. GO to E1.