B: Blower Motor In High In All Blower Motor Switch Positions

B1 CHECK VOLTAGE AT PINS 2 AND 5

- Start engine, set control to MAX A/C, set heater blower motor switch to MED. If A/C blower motor remains in high speeds, proceed as follows:

- Disconnect the A/C blower motor speed control connector. Start engine, set control to MAX A/C and A/C blower motor at low speed. Check voltage between Pins 2 and 5 of the A/C blower motor speed control connector, while changing the A/C blower motor switch settings. Should be between one and two volts for all settings except HI blower. Zero volts at HI blower.

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

- Yes
Go to B4.

- No
Go to B2.

B2 CHECK FOR VOLTAGE IN ALL SWITCH POSITIONS

- Verify voltage measurement.

- Is voltage above 2 volts in all switch settings?

- Yes
Replace control module.

- No
Go to B3.

B3 CHECK FOR ZERO VOLTAGE

- Verify voltage measurement.

- Does voltage measure zero volts in all switch settings?

- Yes
Go to B5.

- No
Retest. GO to B1.

B4 CHECK VOLTAGE AT PINS 3 AND 5

- Check voltage between Pins 3 and 5 of A/C blower motor speed control with A/C blower motor in any speed except HI. Should be zero volts.

- Does voltage measure zero?

- Yes
Replace A/C blower motor speed control.

- No
Replace control module.

B5 CHECK VOLTAGE WITH BLOWER IN MEDIUM SPEED

- Connect harness connector to A/C blower motor speed control. With the engine running, set to MAX A/C and heater blower motor set for medium speed, check voltage at Pin 6 of ATC control module.

- Is the voltage measurement 1-2 volts?

- Yes
Service Circuit between ATC module and A/C blower motor speed control (752 Y/R) or circuit between EATC module and A/C blower motor speed control.

- No
Go to B6.

B6 CHECK VOLTAGE AT PIN 6

- Verify voltage measurement.

- Does voltage measure zero volts?

- Yes
Replace module.

- No
Retest. GO to B1.