Posted by Brian on 16th Jul 2015
Norcold Refrigerator in Lockout Mode (do you need to reset your power board?)
Quick answer: if your Norcold shows NO CO, n, or a light flashing 5 times, it's in lockout mode. The refrigerator asked for cooling but didn't sense the temperature drop, so the power board shut it down for safety.
Your power board is almost certainly not the problem; it's the part doing its job. Reset it using the steps below, then use the cause checklist to find what's really wrong.
Which Lockout Code Do You Have?
| Your model | Lockout code | Parts & diagram |
|---|---|---|
| N611, N811 | Front light flashes 5 times | N611 / N811 parts |
| N621, N622, N821, N822 | Display shows n | N621 / N821 parts |
| N400, N410, N412, N500, N510, N512 | Display shows n | Norcold parts by model |
| N641, N642, NX641, NXA641, N841, N842, NX841, NXA841 | Display shows no co | N641 / N841 parts |
| 1200, 1210, 1211 | Display shows no co | 1200 parts · 1210 parts |
| 2117, 2118 | Display shows no co | Norcold parts by model |
Seeing a different code? See Norcold error codes explained.
Before You Reset: Check the Cooling Unit
Open the outside access panel behind the refrigerator and look under the cooling unit. If you see yellow powder or residue, or smell ammonia (faint or strong), the cooling unit has leaked. Don't reset the board; turn the refrigerator off. A leaking cooling unit can't be repaired, only replaced.
Often the most affordable fix if the rest of the fridge is in good shape.
Shop Norcold cooling units →
Worth comparing on older units or when your cooling unit is no longer made.
Norcold replacement guide →
No residue and no smell? Go ahead and reset the board.
How to Reset a Norcold Power Board
You'll need a short jumper wire (12 gauge recommended) with stripped ends. The refrigerator must be on and showing the lockout code while you do this.
- Remove the power board cover. It's on the back of the refrigerator, reached through the outside access panel: a black rectangular cover with wires attached, held on by a few screws.
- Find the reset pin for your board.
- Older boards (pre-2006): find the 16-pin connector (two rows of 8) at the bottom of the board. The reset pin is the second pin from the left on the top row, an empty slot.
- Newer boards: find the upper 6-pin terminal. The reset pin is the second pin from the right, also an empty slot.
- Jump the pin to a good ground. Touch one end of the wire to the reset pin and the other to ground, and hold for about 10 seconds or until you hear a click.
- Watch the refrigerator. The code should clear and the fridge should start trying to cool again.
Be careful: the board is live while you do this, and there's 120V AC behind the fridge. Touch only the reset pin and ground. If you're not comfortable working on live electrical components, call a qualified RV technician.
Board Won't Reset?
Every Norcold power board can be reset, even a bad one. If yours won't, it's almost always the connection: make sure the wire is solid 12 gauge and pressed firmly on both the pin and the ground. Try a different ground point, such as the ground screw on the board or the grounding plate at the bottom. More tips: My Norcold power board won't reset.
Lockout Came Back? Find the Real Cause
A reset only clears the code so you can troubleshoot. If the cause is still there, the fridge will usually run for 3 to 4 hours and lock out again. Work through these causes, most common first:
| Cause | How to check | Fix |
|---|---|---|
| Off-level operation | Put a level on the freezer floor while parked | Level the RV, then reset |
| Poor ventilation | Blocked roof or side vents, nests, debris behind the fridge | Clear vents · venting guide |
| Cooling fan not working | Fan on the back fins doesn't spin in hot weather | Norcold fans |
| Bad thermistor | Loose on the fins, or out of spec on a meter | Test it · Norcold thermistors |
| Dirty burner or wrong orifice | Locks out on LP only; weak or yellow flame | Clean it · burners & orifices |
| Low AC voltage or heater problem | Locks out on electric only; check voltage and heater resistance | Heater check · AC heaters |
| Improper installation | New install or recently moved fridge; gaps around it, missing baffles | Correct venting and sealing per the install manual |
| Failing cooling unit | Locks out on both AC and LP after everything above checks out | Norcold cooling units · why they fail |
Most Common Replacement Parts That Fix Lockout
In order of how often we see them. Find your model under each part, and confirm the fit with your model and serial number on the product page.
1Thermistor
The thermistor tells the board how cold the fridge is. If it fails or comes loose from the fins, the board never sees the temperature drop and locks out.
Quick check: make sure it's clipped tight to the fins, then test it with a meter.
- N611, N621, N641, N811, N821, N841: Thermistor 618548
- 1200, 1210: Norcold thermistors
- 2117: Freezer thermistor 627873
- 2118: Thermistor 629409
- N400, N410, N412, N500, N510, N512: Thermistor 628760
Related reading: How to tell if your thermistor is bad · Quickly test your Norcold thermistor · Fridge freezing everything?
2Burner / Orifice
A dirty or worn burner gives a weak flame that can't heat the cooling unit, so the fridge locks out on propane.
Quick check: locks out on LP only, or the flame is weak or yellow. Try cleaning the burner first.
- N611, N621, N641, N811, N821, N841: Burner/orifice assembly 621957
- 1200: Burner orifice assembly 629013
- 1210: Burner orifice assembly 635614
- 2117: Burner orifice assembly 630360
- 2118: Burner orifice assembly 638144
- All other models: Norcold burners & orifices
Related reading: Norcold not staying lit on gas · Not working on propane but works on AC · no FL / F flame codes
3AC Heater
In electric mode the heater supplies the heat. A failed or weak heater means no cooling on AC, and the board locks out.
Quick check: locks out on electric only. Unplug the fridge and measure the heater: about 48 ohms on N6/N8 models, about 64 ohms on the 1200/1210. See heater wiring.
- N611, N621, N641, N811, N821, N841: AC heater 638374 (newer units) · all Norcold AC heaters
- 1200, 1210: AC heater 630807
- 2117: AC heater 638369
- 2118: AC heater 637136
- N400, N410, N412, N500, N510, N512: AC heater 630804
Related reading: Are your AC heaters hooked up properly? · Not working on electric · AC HE / H heater codes
4Cooling Unit
If the thermistor, burner and heater all check out and it still locks out on every mode, the cooling unit has likely failed.
Quick check: yellow residue or an ammonia smell behind the fridge, or lockout on both AC and LP. See why cooling units fail.
- N611, N621, N641: Nordic cooling unit 3361A
- N811, N821, N841: Nordic cooling unit 3381A
- 1200, 1210: Nordic cooling unit 6610
- 2118: Nordic cooling unit 6618
- N400, N410, N412: Cooling unit 632294
- N510, N512: Cooling unit 632299
- 2117 and other models: Norcold cooling units
Related reading: How to replace a cooling unit · 1200/1210 cooling units are available · Smells like ammonia? · Bad Norcold cooling unit
Tip: note which mode it locks out on. Lockout on LP only points to the burner. Lockout on electric only points to the heater or AC power. Lockout on both points to airflow, leveling, the thermistor or the cooling unit.
Why a New Power Board Won't Fix Lockout
It's the most common mistake we see. Lockout means the board is working: it noticed the fridge wasn't cooling and protected the cooling unit from overheating. A new board would detect the same problem and lock out again within hours. Save your money for the part that's actually causing it.
Is the Cooling Unit Done? Repair vs. Replace
If you've worked through the list and it still locks out on every mode, the cooling unit has likely failed. You have two options:
- Replace the cooling unit: keeps your existing cabinet, doors and controls. See how to replace a cooling unit, and for 1200/1210 owners, 1200/1210 cooling units are available.
- Replace the refrigerator: often the better choice for older models. N811, N821 and N841 owners, see your replacement options, or browse new Norcold refrigerators.
Still stuck? Send us your model and serial number.
Email a photo of the label inside your fridge and tell us what it's doing. We'll point you to the right part for your exact unit.