2001 Ford Windstar

Check the heater core hoses for heat. If they are hot. Check the blend door

TEST E: INSUFFICIENT/ERRATIC OR NO HEAT
Check engine coolant level hot and cold at coolant reservoir bottle. If coolant is at proper level, go to next step. If coolant level is incorrect, go to step 3.
Start engine and bring to normal operating temperature. Set control to full heat. Feel heater core inlet hose. If heater inlet hose is hot, go to step 4. If heater inlet hose is not hot, check cooling system and hoses. Repair as needed. Retest system.
Ensure cooling system is filled to specified level. Perform cooling system pressure check. If system holds pressure, go to next step. If system does not hold pressure, repair engine coolant leaks as necessary. Retest system.
With engine at normal operating temperature, set control to full heat. Feel heater core outlet hose. If heater core outlet hose is cool, repair heater core for plugged condition. If heater core outlet hose is hot, perform TEST I: NO OPERATION IN ALL TEMPERATURE SETTINGS.

TEST I: NO OPERATION IN ALL TEMPERATURE SETTINGS
Start engine and warm to normal operating temperature. Turn climate control switch to MAX A/C position. Adjust blend door to full cool and check for cool air discharge. Adjust blend door to full warm and check for warm air discharge. Vary blend door from cool to warm. If temperature varied, system is okay at this time. If temperature did not vary, go to next step.
Turn ignition switch to OFF position. Disconnect blend door actuator motor harness connector C242. Turn ignition switch to ON position. Measure voltage between ground and terminal No. 7 (Red/Black wire) at blend door actuator harness connector C242. See Fig. 8. If voltage is greater than 10 volts, go to next step. If voltage is 10 volts or less, repair open in Red/Black wire. Retest system.
Turn ignition switch to OFF position. Measure resistance between ground and terminal No. 8 (Black wire) at blend door actuator motor harness connector C242. If resistance is 5 ohms or less, go to next step. If resistance is greater than 5 ohms, repair open in Black wire. Retest system.
Turn ignition switch to ON position. Measure voltage between ground and terminal No. 3 (Gray/Yellow wire) at blend door actuator motor connector C242 while moving temperature from MAX cool to MAX warm. If voltage varied with movement, replace blend door actuator. Retest system. If voltage did not vary, go to next step.
Turn ignition switch to OFF position. Disconnect climate control switch harness connector C244. Measure resistance of Gray/Yellow wire between terminal No. 3 at blend door actuator motor harness connector C242 and terminal No. 3 at climate control switch harness connector C244. See Fig. 3 and Fig. 8. If resistance is 5 ohms or less, replace climate control switch. Retest system. If resistance is greater than 5 ohms, replace blend door actuator. Retest system.