NO LED
Thermo Pride No Power to Furnace

No LED lights on the control board, furnace completely dead.

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Tripped furnace breaker, Blown internal fuse on Thermo Pride control board, Failed 24V transformer, Open blower door safety switch

How to Fix / Troubleshooting

Safety First: Use caution when working around line voltage. Turn off the breaker before opening electrical compartments.

No LED indicates the control board is not powered.

  • Check breaker and service switch: Verify the furnace breaker in the panel is ON and the furnace service switch is not off.
  • Inspect blower door switch: Ensure the blower door is properly installed and depressing the door switch. Some models will not power the board with the door removed.
  • Check board fuse: Locate the small automotive-style fuse on the control board. If blown, replace with the same amperage. If it blows again immediately, there is a short in the low-voltage circuit.
  • Test transformer (advanced): With power on, measure voltage at the primary and secondary of the transformer. If primary has 120V but secondary has 0V, replace the transformer.

When to call a professional: If fuses continue to blow or you cannot identify the power loss, contact an HVAC technician.

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Repair Difficulty

Medium 3/5

Required Part

Control Board Fuse
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