Test G: Blower Motor Does Not Operate In Some Settings

WARNING: This page is about a different car, the 1999 Lincoln Navigator and 1999 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.

Inspect Connectors

Turn ignition off. Disconnect EATC module connector (C281). Disconnect blower motor speed controller connector. Inspect Tan/Orange wire pins in both connectors for signs of damage or looseness. If damage or looseness is noted, repair connector pins. Retest system. If pins are okay, replace EATC module. Retest system.

Check Blower Motor Operation

Turn ignition to run position (engine off). Press MAX A/C button. Adjust blower speed setting from LO to HI position. If blower speed increases with movement of blower speed override from LO to HI position, system is functioning properly at this time. If blower speed does not increase with movement of blower speed override from LO to HI position, go to next step.

Check Blower Speed Controller Input Voltage

Turn ignition off. Disconnect EATC module connector (C281). Turn ignition to run position (engine off). With a voltmeter, measure voltage of Tan/Orange wire between EATC module connector C281 and ground. If voltage is more than 4.6 volts, go to step 6) . If voltage is less than 4.6 volts, go to next step.

Check Tan/Orange Wire For Short

Turn ignition off. Disconnect blower motor speed controller connector. With an ohmmeter, measure resistance of Tan/Orange wire between EATC module connector C281 and ground. If resistance is more than 10,000 ohms, go to next step. If resistance is less than 10,000 ohms, repair short to ground in Tan/Orange wire. Retest system.

Check Tan/Orange Wire For Open

Measure resistance of Tan/Orange wire between EATC module connector C281 and blower speed controller connector. If resistance is less than 5 ohms, replace blower motor speed controller. Retest system. If resistance is more than 5 ohms, repair open in Tan/Orange wire. Retest system.

Check For Disruption In Control Signal

Turn ignition off. Reconnect EATC module connector (C281). Without disconnecting blower motor speed controller connector, use a voltmeter to measure voltage of Tan/Orange wire between blower motor speed controller connector and ground. Note voltage.
Turn ignition to run position (engine off). Press MAX A/C button. Adjust blower speed to HI position. Slowly adjust blower speed downward, observing voltmeter. Watch for disruption as voltage decreases. Voltage should decrease in steps from 5 volts to a point less than 1 volt. If voltage decreased without disruption, system is functioning normally. If there were disruptions in voltage, replace EATC module. Retest system.