Goodman Furnace: Open fuse, no furnace operation
Open fuse, no furnace operation on a Goodman furnace: The furnace is dead or won't run, and the 3-amp control fuse on the board has blown. That fuse protects the 24 V side, so a blown one almost always means something is shorting in the low voltage wiring. Just swapping the fuse usually gets you another blown fuse a minute later.
Applies to: 34.5 in chassis gas furnaces
Common causes of open fuse, no furnace operation
- Open fuse
- Short in low voltage wiring, such as a pinched or chafed thermostat wire, a staple through the cable, or a bad accessory like a humidifier or relay
How to fix open fuse, no furnace operation: step by step
- Turn power off before repair.
- Locate and correct the short in the low voltage wiring.
- Look along the thermostat wire runs and at the cabinet edges where the wire passes through. Disconnect any add-ons one at a time to see if one is the cause.
- Replace the fuse with a 3-amp automotive type fuse.
- Restore power and watch the furnace through a full cycle.
If the unit shows an error code, look it up: Goodman Furnace codes
Source: Goodman GMVC96 Service and Troubleshooting, p. 61. Written in our own words as a summary; always check the original manual.
General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.