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1990-1996 Corvette Air Conditioning Controls Services

90-96 C68 ECC HVAC Controller Module

 

The Controller module acts as the keyboard and display for a computer located elsewhere (the programmer module).

 

Common Problems with the Controller Module

  • Nonworking Button(s) / Won't Change Modes

  • Faded Display

  • The bulbs which illuminate the cluster remain dark, even with the ignition on.

 

The Programmer Module

The programmer module is the computer and the power supply for the HVAC system, as well as the solenoid block which directs the vacuum actuators on the air handling box to divert air through or around the evaporator or heater cores, and out specific vents. The programmer module generates the AC Compressor Clutch request signal.

 

Common Problems with the Programmer Module

  • When the ignition is on, the LCD turns orange but remains blank (or shows "---"), and the info can't be seen

  • The operating mode can't be selected, and the yellow LEDs don't light up above the correct mode button

  • The vents blow cold air in the winter, or blow warm air in the summer

  • The AC compressor doesn't engage when an AC mode is selected.

  • The plastic used in the factory vacuum connector assembly can become heat- and age-damaged.

  • Programmers have to be removed for service due to aging.  The removal process is difficult and the vacuum assembly can be damaged during removal or reassembly.

  • The plastic in the vacuum system is delicious to rodents.  About one in ten programmers that we see has rodent damage!

  • 94-96 programmers are made with a soft plastic that has become too soft over time.  It closes up under vacuum and causes the air to blow out the top or bottom vents instead of toward the driver.

 

  • The Air Filters on the solenoids have rotted away.

 

Rebuilt Programmer Vacuum System

 

The Blend Door Motor

The blend door motor moves the blend door inside the air handling box. This causes more or less air from the blower to flow through the heater core, causing the air coming from the air handling box to be warmer or cooler. We can test this, but most repairs involve parts that are no longer available.

 

Common Problems with the Blend Door Motor

  • The vents blow hot air when they should blow cool, or vice versa

  • Moisture and dust from the system can cause the motor to seize or the gearbox to fail

  • The position sensor becomes uncalibrated or wears out over time

  • Blend door motor oscillates back and forth at about one cycle per second

 

The Blower Control Module

The Blower Control Module is the electronic speed controller for the blower motor.

 

Common Problems with the Blower Control Module

  • The Blower Control Module transistor fails frequently. It typically fails shorted, causing the fan motor to run when it shouldn't.

  • We can test this component, but it is sealed and not repairable.

 

All Services Include

  • Free inspection of the Electronic Climate Control internals

  • Free electrical diagnosis, complete with photos of the problem(s)

  • Complete cleaning inside the controls

  • Bench test of all bulbs, blend door motor, and all other climate control functions

  • 1 year warranty on parts and labor

  • This is not an exchange service. Your components will be returned to you, along with the parts we replace!

 

Pricing

  • Controller standard electrical repairs: $125.00
  • Programmer standard electrical repairs: $125.00 - or
  • Programmer Complete Rebuild (Electrical+Vacuum Service):  $300.00
  • Send everything you want tested - there's No Charge for testing!  

     

    Note: These repairs are the most common needed for the 90-96 ECC, and do not include replacement of missing parts, and do not include replacement of the display or logic board. When your components arrive, we will diagnose them at no charge, then contact you with photos of the problem and an exact repair total, then wait for your approval before making any repairs.

     

    Before Shipping To Us

    • Check the CTSY, CLUSTER, AC and AC Underhood fuses.
    • If the LED above the selected mode button is flashing, press the FAN UP and FAN DOWN buttons simultaneously for five seconds to enter diagnostic mode.
      Diagnostic codes will be displayed on the LCD. Send us those diagnostic codes.
    • The programmer module is located in the drivers side footwell, just above the gas pedal. Follow the colored vacuum lines to the module. There is a metal keeper holding the block of vacuum lines on. Disconnect it with a pair of needle nose pliers or cut the push-on nut with side cutters, then remove the vacuum lines as a group.  We return the programmer with a lock nut that allows you to reattach the vacuum lines.
    • If you are experiencing temperature problems following a drained battery, the programmer can lose the blend door motor calibration.  Try this before shipping to us:
      • Pull the AC and CTSY fuses
      • Wait 5 minutes
      • Put both fuses back
      • Turn key on but leave engine off.
      • AC Controller should turn itself on.  If not, push AUTO.
      • Wait 15 minutes for the blend door calibration process to complete.  During this process, listen in the passenger footwell to see if you hear the geared blend door moving.
      • Cycle the key off and on
      • Re-test the heat or AC operation.  If it's still not working, send us the programmer and optionally the blend door motor (esp if you didn't hear it moving during the test).