Status LED flashes code 24 (two short, four long). Furnace does not respond to thermostat; no inducer or blower operation.

Safety first: Turn off power before replacing fuses or inspecting wiring. Do not bypass the fuse with foil or a larger fuse.

• Locate and inspect the fuse: Remove the blower door and find the small automotive-style blade fuse on the Payne control board. If it appears melted or open, it is blown.
• Check for shorts: Before replacing the fuse, inspect all low-voltage wiring (R, W, Y, G, C) for bare copper touching metal or other wires. Pay special attention where wires pass through sheet metal.
• Disconnect external loads: Temporarily disconnect thermostat wires at the furnace (label them first). Install a new fuse of the same rating (usually 3A or 5A). Restore power. If the fuse holds with thermostat disconnected, the short is in the thermostat cable or thermostat.
• Reconnect circuits one by one: Reconnect R and C, then W, Y, G individually to identify which circuit blows the fuse.
• Repair damaged wiring: Replace or splice any damaged thermostat cable using proper wire nuts and electrical tape. Secure wires away from sharp edges.