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Goodman · Furnace troubleshooting

Display blank, furnace dead - Goodman *MVC95/*CVC9

Goodman/Amana *MVC95/*CVC9 two-stage ComfortNet

What is going on

The two-digit display shows nothing and the furnace does nothing. A ComfortNet thermostat may show INTERNAL FAULT EE with Call for Service.

Likely causes

  • Disconnect switch off, blower door switch open, or 24 V wire loose
  • Blown fuse or tripped breaker
  • Internal fault in the furnace control

Check in this order

  1. Safety turn power off before touching the control. Discharge static to a bare metal part of the cabinet first.
  2. Confirm 115 V at the furnace and that the blower door is closed on its switch.
  3. Check for 24 V at the control.
  4. Check the 3 A fuse on the control. Replace with a 3 A automotive fuse only, after you find any short in the 115 V or 24 V wiring.
  5. If power and fuse are good and the display is still blank, replace the control with the correct part.

Applies to: GMVC95/AMVC95 upflow and *CVC9 counterflow two-stage furnaces

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Source: Goodman *CVC9/95 & *MVC95 Installation Instructions IO-341D (08/2010), Troubleshooting Chart p.53; Electrostatic Discharge p.49. Written in our own words; check the manual for your exact model.

For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.