Test B: EATC System Inoperative, Intermittent Or Operates Improperly
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.
- Perform EATC Self-Diagnostics
Turn ignition to run position (engine off). Perform EATC self-diagnostics. See ENTERING SELF-DIAGNOSTICS under SELF-DIAGNOSTICS. If any DTCs were displayed, see SELF-DIAGNOSTIC TEST CODE DIRECTORY table. If no DTCs were displayed, go to next step. - Check Vacuum Fluorescent Display
Exit self-diagnostics by pressing DEF (defrost) button. Observe symbols displayed. If the display is complete, with no missing elements, go to next step. If display is incorrect or incomplete, replace EATC module and retest system. - Verify Automatic Operation
Press AUTOMATIC button. If AUTO appears in display window, go to next step. If AUTO does not appear in display window, go to TEST H . - Check Blower Manual Override High Speed Operation
Slowly rotate blower speed control to full up (high speed) position. If blower motor speed goes smoothly to high speed, go to next step. If blower motor speed does not change properly, go to TEST G . - Verify Blower Manual Override Low Speed Operation
Slowly rotate blower speed control to full down (low speed) position. If blower motor speed goes smoothly to low speed, go to next step. If blower motor speed does not change, go to TEST F . - Verify Defrost Override Operation
Press DEF button. If outside air is discharged only to windshield and side window demisters, go to next step. If air is not discharged as indicated, go to TEST C . - Verify Floor Override Operation
Press FLOOR mode button. If outside air is discharged from floor duct, go to next step. If air is not properly discharged from floor duct, go to TEST C . - Verify Vent Override Operation
Press VENT mode button. If outside air is discharged from instrument panel registers, go to next step. If air does not flow properly from panel registers, go to TEST C . - Verify Compressor Clutch Does Not Engage In Vent Mode
Press VENT mode button. If compressor clutch does not engage, go to next step. If compressor clutch engages, problem may be in PCM circuit. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE. - Verify MAX A/C Override Operation
Check that ambient air temperature is above 41°F (5°C). Press MAX A/C button. If recirculated air is discharged from panel registers, go to next step. If air is not recirculated, go to TEST C . - Verify Compressor Clutch Engages In MAX A/C Mode
Press MAX A/C button. If compressor clutch engages, system is operating normally. If compressor clutch does not engage, go to TEST D .