FOUR MOST COMMON MARAUDER HVAC PROBLEMS

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FOUR MOST COMMON MARAUDER HVAC PROBLEMS

PROBLEM: Air blows out of the defrost vents instead of where it should or may come out where it's supposed to until you accelerate, then the air comes out the defrost.
Most likely the o-rings on the solenoids, inside the Electronic Automatic Temperature Control (EATC), need to be replaced. The cheap rubber hardens over time causing a vacuum leak. I’ve replaced some that are so brittle that they break into pieces when I remove them. You will probably see that all four o-rings are square, square doesn’t seal a round cylinder very good. They should be replaced with high quality silicone o-rings and a small amount of silicone dielectric grease. If you buy another EATC, even a new one, you will eventually need to replace the o-rings.

Could also be a vacuum leak inside the car or under the hood.

Could also be the electronics inside the EATC.

NOTE: If you disconnect the vacuum connector from the EATC you might notice that there is one hose “missing”. It’s not supposed to be there. Looking at the nipples on the back of the EATC one has no opening.

PROBLEM: Blower doesn’t work or only blows at one speed.
Most likely it is the Blower Control Module (BCM). Tap the BCM (under the hood, behind the passenger side cam cover). If tapping the BCM makes the blower work correctly, the BCM needs to be replaced. Buying a new BCM (only buy a new one from FORD – aftermarket ones have a poor track record) will fix the problem but it will probably happen again due to the type of solder used. If tapping the BCM doesn’t make the blower come on then you probably need a new blower motor or the fan control / electronics inside the EATC can be bad.

PROBLEM: Temperature doesn’t regulate, its either too hot or too cold and or knocking noise coming from center of the dash.
Run the EATC self test, if you get an "024" or "025" code the Blend Door Actuator is bad. A code of "888" means all is OK as far as the self test is concerned.
The BDA moves a door that closes off either the heater core or the evaporator, providing just the right mix of hot or cold air depending on the temperature setting in the EATC. When the BDA goes bad it doesn’t move at all or it rapidly moves back and forth creating a knocking noise. The only fix is to replace the BDA. The part is less than $100.00 and again only buy a FORD one! Don’t buy an aftermarket as you don’t want to do the job again or pay the labor to get it done again as the dash need to come apart.

PROBLEM: No A/C
The A/C system is a closed system. If it is blowing warm or hot air, most likely there is something wrong with the A/C system. If you have to add freon to get the system to work, you have a leak in the system and unless you are experienced and licensed to work on the A/C systems (in most states) you need to take it to a professional. One of the most common problems is the bottom of the receiver / dryer rusts out due to its construction and location. If it needs to be replaced insist on an aluminum replacement part.

Electronic Automatic Temperature Control Module Self-Test

• The EATC module self-test will not detect concerns associated with data link messages like engine coolant temperature or vehicle speed signals. A NGS tester must be used to retrieve these concerns.
• The EATC module self-test will detect concerns in the system control functions and will display hard diagnostic trouble codes (DTCs) in addition to intermittent diagnostic trouble codes for concerns that occur during system operation. The vehicle interior temperature should be between 4°-32°C (40-90°F) when carrying out the self-test. If the temperatures are not within the specified ranges, false in-car temperature sensor DTCs will be displayed.
• The self-test can be initiated at any time. Normal operation of the system stops when the self-test is activated.
• To enter the self-test, press the OFF and FLOOR buttons simultaneously and then press the AUTOMATIC button within two seconds. The display will show a pulse tracer going around the center of the display window. The test may run as long as 30 seconds. Record all DTCs displayed.
• If any DTCs appear during the self-test, follow the diagnostics procedure given under ACTION for each DTC given.
• If a condition exists but no DTCs appear during the self-test, refer to the Symptom Chart Condition: The EATC System Is Inoperative, Intermittent or Improper Operation.
• To exit self-test and retain all intermittent DTCs, push the blue (cooler) button. The control will exit self-test, retain all intermittent diagnostic trouble codes and then turn OFF (display blank).
• To exit the self-test and clear all DTCs, press the DEFROST button. The vacuum fluorescent display window will show 888 and all function symbols for one second. Then, the EATC control assembly will turn OFF (display blank) and all DTCs will be cleared.
• Always exit the self-test before powering the system down (system turned OFF).
• Intermittent DTCs will be deleted after 80 ignition switch ON cycles after the intermittent condition occurs.