Goodman Furnace: Check thermostat and low voltage wiring
Check thermostat and low voltage wiring on a Goodman furnace: Decides whether a no-heat or no-cool problem is in the thermostat or the wiring, or in the furnace.
Applies to: Gas furnaces ACVC96/AMVC96/GCVC96/GMVC96
How to fix check thermostat and low voltage wiring: step by step
- Remove the blower compartment door and disconnect the thermostat low voltage wires at the furnace control terminals.
- Jumper R to W (or W1 and W2 on two-stage models) on the integrated ignition control.
- With power on and the door interlock closed, the induced draft motor must run and pull in the pressure switch.
- If the hot surface ignitor heats and the gas valve opens and the burners light, the fault is in the thermostat or wiring.
- With power off, check continuity of the thermostat and wiring. Repair or replace as needed.
- To check cooling mode, with power off jumper R to Y (or Y1/Y2) to G, then turn power on.
- If the blower starts and the condensing unit runs, the fault is in the thermostat or wiring.
- Reinstall the blower compartment door and verify operation.
Safety: Gas, electrical and refrigerant work must be done by a licensed technician. Turn off power and gas before servicing, never bypass a safety control, and always follow the manufacturer's manual for your exact model.
If the unit shows an error code, look it up: Goodman Furnace codes
Source: Goodman GMVC96 service and troubleshooting manual, p. 43. 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.