14th Oct 2026
Norcold N4000 Error Code 13 (Thermistor Failure)
CODE 13
Norcold N4000 Error Code 13 (Thermistor Failure)
The control can’t read the thermistor, the temperature sensor on the cooling fins, so it switches to its Backup Operating System and keeps cooling on a timer.
Before you start
- Where things are. The power board, fuses, burner and heaters are behind the lower outside vent on the back of the fridge. The control panel is on the front, at the top.
- Where it is. The thermistor clips onto the 5th fin from the right inside the fridge.
Fits these models
The Norcold N4000 series, built by Thetford. 3-way (12V DC, 120V AC and propane).
How to read this code
LED panel: press the ‹, □ and › buttons together until the temperature bars change. The lit bars spell the code in binary. This pattern is code 13.
LCD panel: the code number shows next to the wrench symbol.
No 12 volts, no code: the controls need 12V DC to show any error. With 12V, the blue power light is on.
STEP 1
Check the thermistor is there
Look for the thermistor on the cooling fins.
Is it present?
Install the thermistor
Fit it on the 5th fin from the right.
STEP 2
Check the plug
Check the thermistor’s plug at its connector.
Is it plugged in correctly?
Plug it in
Seat it fully, then turn the fridge off and on.
STEP 3
Check the wiring loom
Check that the wiring loom is connected correctly to the power board.
Is it?
Connect it correctly
Reseat the loom plug.
STEP 4
Check the plug pins
Check the pins in the wiring loom plug.
Are they present and not bent or loose?
Fix the pins
Repair them if possible.
STEP 5
Test the cable
Check the thermistor cable for continuity.
Does it have continuity?
Replace the cable
Replace the thermistor cable.
STEP 6
Replace the thermistor
Install a new thermistor.
Is code 13 gone?
Fixed
The thermistor had failed.
Replace the power board
Replace the power board. Match the part number on your old board; see the N4150, N4141 or N4104 parts or ask a tech.
Still stuck? ask a tech with your model, serial number and the code you’re seeing. We’ll confirm the part before you order.
Covers the Norcold N4104, N4141 and N4150. Based on Thetford’s N4000 troubleshooting guide (Error code 13), with North American voltage and gas pressure values.