K: EATC BLOWER MOTOR OPERATES IN HIGH IN ALL SWITCH POSITIONS

PINPOINT TEST K: EATC HEATER BLOWER MOTOR OPERATES IN HIGH IN ALL BLOWER WHEEL POSITIONS

K1 CHECK BLOWER MOTOR MEDIUM SPEED OPERATION

- Start engine, select MAX A/C and position the blower thumbwheel midway between HI and LO. The blower motor should operate at approximately medium speed.

- Is the A/C blower motor speed reduced from high speed?

- Yes
Perform Pinpoint Test A.

- No
Go to K2.

K2 CHECK VOLTAGE AT BLOWER SPEED CONTROLLER

- Disconnect the harness connector from the A/C blower motor speed control. Start engine, set control at MAX A/C and blower thumbwheel at LO.
- Check for voltage between Pins 1 and 3 of the harness connector while rotating the blower motor thumbwheel. The voltage reading should be between 1 and 2 volts for all thumbwheel settings except HI; should have zero volts at HI.

- Is voltage measurement between 1 and 2 volts except in HI?

- Yes
Go to K5.

- No
Go to K3.

K3 REVERIFY VOLTAGE IN K2

- Verify the voltage measurement in Step K2.

- Is the voltage measurement above 2 volts in all thumbwheel settings?

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

- No
Go to K4.

K4 ZERO VOLTAGE CHECK

- Refer to voltage measurement taken in Step K2.

- Is the voltage measurement zero volts for all thumbwheel positions?

- Yes
Go to K6.

- No
Retest and Go to K1.

K5 VOLTAGE CHECK AT ANY POSITION EXCEPT HI

- Check voltage between Pins 2 and 1 of A/C blower motor speed control with the blower speed thumbwheel at any position except HI. Should be zero volts.

- Is the voltage measurement zero?

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

- No
Replace the EATC control assembly. Restore vehicle. Retest system.

K6 VOLTAGE CHECK AT EATC PIN 7

- Reconnect harness connector to A/C blower motor speed control. With the engine running, select MAX A/C and set the blower thumbwheel for a medium speed. Check the voltage at Pin 7 of the EATC control assembly.

- 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 EATC control assembly Pin 7 and the A/C blower motor speed controller Pin 2. Restore vehicle. Retest system.

- No
Go to K7.

K7 VERIFY ZERO VOLTAGE

- Verify the voltage measurement taken in Step K6.

- Is the voltage measurement zero volts?

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

- No
Retest voltage. Go to K1.