Goodman · Furnace

EE5 Open fuse (short in low voltage wiring)

Medium severity Goodman/Amana GM9S96/AM9S96Goodman/Amana GM9S80/AM9S80Goodman/Amana GM9C96/AM9C96

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: Goodman/Amana/GMC gas furnaces, 9-speed ECM, 7-segment control. Two-stage 96%: AC9C96, AM9C96, GC9C96, GM9C96. Single stage 80%: VC9S80, VM9S80, AC9S80, AM9S80, GC9S80, GM9S80. Single stage 92/96%: VC9S96, VM9S96, AC9S96, AM9S96, AM9S92, GC9S96, GM9S96, GM9S92

Likely causes

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

Test and repair steps

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.
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.
Repair the shorted wire (often a nicked thermostat cable or a shorted contactor coil), then replace the fuse with one of the same rating.
Restore power and run heat and cool calls to confirm.

Settings for these units

Normal status displays (7-segment) · Goodman/Amana GM9S96/AM9S96
Normal status displays (7-segment) · Goodman/Amana GM9S80/AM9S80
Normal status displays (7-segment) · Goodman/Amana GM9C96/AM9C96
Minimum recommended filter size · Goodman/Amana GM9C96/AM9C96

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Source: Goodman RS6612022r1 (GM9S92/GM9S96/GC9S96 service), 1 Stage Troubleshooting Codes, p.29-30; Goodman RS6621008r2 (GM9S80 service), p.32-33; Goodman RS6612020r1 (GM9C96 service), 2 Stage Troubleshooting Codes, p.35-36; Checking Integrated Ignition Control Boards p.25 (RS6612022r1). Summarized in our own words; check the original manual for your model.

Homeowner looking at this code? See what it means for you and when to call a technician.

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.