IMAGE COMING SOON
OEM Guaranteed
Same-Day Ship
30-Day Returns
Secure Checkout
The Goodman 20162906 M4 Primary Limit Switch is a genuine OEM auto-reset thermal safety control for the GKS91155DXAF gas furnace. Mounted on the heat exchanger, this high-limit switch opens the control circuit if the furnace overheats — shutting off the burners to protect the heat exchanger and prevent unsafe operation.
Limit switches are calibrated to a specific trip temperature for your furnace. A generic switch with the wrong setpoint can nuisance-trip (short-cycling, no heat) or fail to protect the heat exchanger. This genuine Goodman M4 switch trips at the factory-rated temperature for correct, safe protection.
Easy (2/5) — Two screws and a pair of push-on terminals. About 10–15 minutes with a nut driver. Cut power at the breaker before servicing.