D: No High Heater Blower Motor Speed

D1 CHECK BLOWER MOTOR SPEED

- Start engine, set control to MAX A/C, set heater blower motor switch to LO or MED (blower turns), then switch heater blower motor to HI. If heater blower motor does not go to full HI speed, proceed as follows:

- Turn ignition switch OFF.

- Disconnect A/C blower motor speed control connector. Start engine, set control to MAX A/C and A/C blower motor on HIGH. Check voltage between A/C blower motor speed control Pins 3 and 5. Should be 10 or more volts.

- Is voltage 10 volts or greater?

- Yes
Replace A/C blower motor speed control.

- No
Go to D2.

D2 CHECK VOLTAGE AT HIGH SPEED

- Reconnect A/C blower motor speed control connector. With engine running, set control to MAX A/C and A/C blower motor at HI, check for voltage between Pin 5 of the ATC control module and ground. Should be 10 or more volts, when heater blower motor switch is on HI.

- Is voltage 10 volts or greater?

- Yes
Service circuit between ATC control module and A/C blower motor speed control (754 LG/W) or circuit between EATC module and A/C blower motor speed control.

- No
Replace ATC control module.