EE5 Open fuse (short in low voltage wiring)

What the control is telling you

The low-voltage fuse on the control board is open, usually because of a short in the 24 V wiring (thermostat, outdoor unit or accessory wiring).

Applies to: Daikin DR96TN (upflow/horizontal) and DD96TN (downflow/horizontal) two-stage 96% furnaces with 9-speed ECM motor, R-32 ready

Likely causes

• Short in thermostat, outdoor unit or accessory 24 V wiring
• Fuse failed

Test and repair steps

1. Measure R to C if the transformer secondary shows 24 VAC but R-C on the terminal board reads only about 13 VAC, the board fuse is blown.
2. Before replacing the fuse, find the short: disconnect thermostat and outdoor unit wires and check each run for a short to ground or between conductors.
3. Repair the shorted wire (often a nicked thermostat cable or a shorted contactor coil), then replace the fuse with one of the same rating.
4. Restore power and run heat and cool calls to confirm.

Settings for these units

Normal status displays (7-segment) · Daikin DR96TN/DD96TN

These are normal operating displays, not fault codes.

Models that show this code

13 models in Daikin DR96TN/DD96TN

Other codes on the same units

• EE1 Pressure switch closed at start of heating cycle
• EE2 Pressure switch did not close (inducer runs, no ignition)
• EE3 High (primary) limit open
• EE4 Flame sensed with no call for heat
• EE6 Low flame signal
• EE8 High-stage pressure switch closed at start of heating cycle
• EE9 High-stage pressure switch did not close
• EAF R-32 sensor communication lost - mitigation mode