Red + Green LEDs solid
5A replaceable fuse is bad
This code typically points to
- Blown low-voltage fuse from short
- Field wiring short (thermostat, outdoor, accessory)
- Shorted contactor coil
Next checks to confirm
- Check fuse physically first
- Isolate low-voltage short by disconnecting branches one at a time
- Inspect thermostat, outdoor, and accessory wiring
Escalation
Repeated fuse failure means a real low-voltage short — not bad luck. Find and fix the short before replacing fuse.
Reset behavior
Fault remains until fuse is replaced and short corrected.
Urgent
Fix now