Posted by Sr Tech Brian on 12th Oct 2026
Norcold N7X/ N8X Flashing One Time/ AC Heater Fault (quick fix!)
FLASH PATTERN 1
Norcold N7X / N8X AC Heater Fault
The red light flashes once, goes off for 5 seconds and repeats. The fridge tried to run on 120V electric and the AC heater didn’t come on, so it locked out electric mode. It usually still cools on propane.
Before you start
- Reset it once. Turn the fridge OFF, then back ON. If the code doesn’t come back, it may have been a power blip.
- Check the outlet. The fridge needs 108–132 volts AC.
- Check the circuit. Nothing else (another appliance or lights) should share the fridge’s AC circuit.
- Stay safe. Unplug the fridge from 120V before touching heater wires or connectors.
STEP 1
Inspect the AC heater wires
Open the lower outside vent. Follow the AC heater leads from the cooling unit to the power board and look for loose, burnt or damaged connectors.
Are the heater connections okay?
Repair or replace the connectors
If a connector can’t be repaired, replace the AC heater.
Norcold AC Heater 638374 →Fits the Polar N7X and N8X.STEP 2
Measure the AC heater resistance
With the fridge unplugged, disconnect the heater leads and set a multimeter to ohms (Ω). Touch one probe to each heater lead.
Does it read 38–50 ohms?
Replace the AC heater
A reading outside 38–50 ohms (or no reading at all) means the heater has failed open.
Norcold AC Heater 638374 →Fits the Polar N7X and N8X.The heater is good. Replace the power board
The heater checks out, so the board isn’t sending it power. Replace the main control board (power board assembly).
Norcold Power Board 639593 →Main control board for the Polar N7X and N8X.Based on the Norcold Polar N7V/N7X/N7LX/N8V/N8X/N8XL service manual, Fault Code Flash Pattern 1.