Carrier 58MVP Furnace Display Code Continuous ON: Normal Operation
What Does Code Continuous ON Mean?
A continuous-ON LED on the Carrier 58MVP's variable-capacity control board is the board's way of confirming it has power and is healthy. Carrier's guide describes it simply as the control having 24 VAC power. This is a status indication, not a fault, and no action is needed.
On this variable-speed furnace the control board manages the inducer, hot surface igniter, gas valve, the separate low- and high-heat pressure switches, and the ECM blower. A solid LED while the furnace is idle confirms the transformer and low-voltage circuit are working. When a call for heat begins, you may instead see blink codes that report the last stored status. This steady indication is the opposite of a dark LED (no power) and a rapidly flashing LED (reversed line-voltage polarity), both of which point to problems.
What You'll Notice
- The control board LED glows steadily (solid) with no blinking while the furnace is idle
- The furnace starts and heats normally when the thermostat calls for heat
How This Is Diagnosed
To confirm this is truly normal, watch the LED with the furnace idle — a steady light means 24 VAC is present and the board is in standby. If you want the fault history instead, the 58MVP board reports its last stored status as blink codes; a continuous-ON LED together with normal heating simply means nothing is currently wrong.
Frequently Asked Questions
My Carrier 58MVP light is solid/steady — is that bad?
No, a steady (continuous ON) LED is the normal standby indication. It means the board has power and is ready to run when the thermostat calls for heat.
The light is on but there's no heat — what now?
A solid LED only confirms the board has power. If there is no heat, check the thermostat setting and batteries; if those are fine, the call-for-heat signal or another component may be at fault.
Sources
✓ Verified against manufacturer service manual — March 2026