How To Reset A Norcold RV Fridge: Step-by-Step Hard Reset & Troubleshooting Guide

To reset a Norcold RV refrigerator experiencing a "no co" lockout or a tripped thermal recall switch, you must perform either a control board jumper reset or clear the safety limit switch. This process involves temporarily grounding Pin 2 on the power module control board to clear the microchip lockout, or using a strong magnet to reset the High Temperature Limit Switch on the burner flue. Performing these resets restores 12V DC power to the optical display and allows the cooling cycle to restart safely.

Pre-Reset Inspection & Essential Tool Checklist

Gas absorption refrigerators, such as those manufactured by Norcold, rely on a pressurized mixture of ammonia, water, hydrogen, and sodium chromate to cool. When the refrigerator detects a lack of cooling over a specified duration, the electronic control board triggers a hard lockout to prevent the boiler assembly from overheating, which is a major RV fire hazard.

Before attempting any reset, verify that the RV is parked on a level surface. Absorption refrigerators rely on gravity to circulate the liquid ammonia mixture. Operating a Norcold unit out of level by more than three degrees side-to-side or six degrees front-to-back causes the liquid to pool in the cooling coils, stopping circulation and triggering a "no co" error code.

Required Materials, Tools, and Safety Specifications

• Jumper Wire: A 6-inch piece of insulated 18-gauge copper wire stripped 1/4-inch at both ends.
• Neodymium Magnet: A strong, rare-earth magnet (minimum 15-pound pull force) for resetting the High Temperature Sensor (HTS) recall kit.
• Nut Driver & Screwdriver Set: A 1/4-inch nut driver or Phillips screwdriver to remove the black plastic protective cover on the control board.
• Digital Multimeter: To verify 12V DC supply voltage at the terminal block (optimum range: 10.5V DC to 15.4V DC).
• Safety Equipment: Insulated work gloves and safety glasses.
• Estimated Cost: $0 to $15.
• Estimated Duration: 15 to 30 minutes.

Step-by-Step Norcold Control Board Reset Procedures

The modern Norcold electronic control system uses non-volatile memory to store safety lockouts. Simply disconnecting the battery or turning off the refrigerator will not clear a hard lockout error such as "no co" or a flashing "n". Use the following technical procedures to clear these safety codes.

Step 1: Diagnose the Lockout Type

Examine the optical control panel inside the RV. If the display shows "no co" (on digital models) or if the LED lights are flashing rapidly in a specific sequence (on manual/three-way models), the main board has registered a cooling failure. If the display panel is completely dead despite having a fully charged 12V house battery system, go to the exterior refrigerator access panel. Inspect the small black recall box mounted on the silver burner flue. If the red light on this recall box is illuminated, the high-temperature safety switch has tripped, cutting off 12V power to the entire unit.

Step 2: Clear Soft Lockouts via Power Cycling

Before performing a physical hard reset on the control board circuitry, attempt a soft reset to rule out temporary sensor glitches.

1. Turn off the refrigerator using the front control panel power button.
2. Go to the exterior access panel of the RV and locate the 120V AC power cord plugged into the outlet receptacle. Unplug it.
3. Locate the main 12V DC power connection block on the control board (usually marked with positive and negative terminals).
4. Disconnect the positive 12V DC wire (typically red or blue) from the board to completely isolate the memory chip.
5. Wait exactly ten minutes to allow all internal capacitors on the circuit board to drain completely.
6. Reconnect the 12V DC positive wire, plug in the 120V AC cord, and turn the refrigerator back on from the interior panel. If the code persists, proceed to the hard jumper reset.

Step 3: Gain Access to the Power Control Board

1. Ensure the propane gas valve at the RV tanks is turned off to eliminate any ignition hazards during electrical testing.
2. Remove the exterior plastic vent cover on the side of the RV.
3. Locate the black plastic cover protecting the main power module control board.
4. Use a 1/4-inch nut driver or screwdriver to remove the retaining screw securing the plastic cover, then carefully unclip and remove the cover to expose the circuitry.

Step 4: Execute the Hard Jumper Reset (Clearing "no co" or "n" Codes)

This procedure bypasses the memory circuit temporarily to clear the lockout counter. Do not let the jumper wire touch any other components on the circuit board, as this can permanently fry the microprocessor.

1. Locate the main 16-pin wiring harness plug connected to the bottom or side of the control board.
2. Inspect the plug to locate Pin 2. On standard Norcold boards (such as those on the 1200, 1210, 9100, and N-series), Pin 2 is typically a vacant slot next to the yellow wire, or it may contain a yellow wire depending on the specific board generation.
3. Have an assistant turn the refrigerator ON at the interior display panel. The error code will still be visible or flashing.
4. Take your prepared 18-gauge jumper wire and insert one bare end directly into the back of Pin 2 on the 16-pin connector.
5. Touch the other stripped end of the jumper wire to the main ground terminal screw on the metal burner bracket assembly or the ground wire input terminal (marked GND).
6. Hold this connection steady for exactly 10 to 15 seconds. You should hear a distinct click from one of the 12V DC relays on the board.
7. Remove the jumper wire immediately. The interior display panel should now show normal operating characters, and the cooling unit should initiate its startup sequence.
8. Reinstall the black plastic protective cover and secure it with the screw.

Step 5: Reset the High-Temperature Recall Switch (Magnet Method)

If the safety recall box (installed under the Norcold safety recall program) has tripped due to an electrical surge, car wash spray, or a brief temperature spike, it cuts off the 12V DC current. You can reset this switch using a strong magnet if the cooling unit itself has not ruptured.

1. Locate the small black box (about two inches square) attached to the round metal boiler tube casing.
2. Identify the red LED light on the face of this box. If it is glowing red, the internal magnetic reed switch has opened.
3. Take your strong neodymium magnet and place it directly against the plastic casing of the recall box, centered right next to the illuminated red LED.
4. Move the magnet slowly in a small circular pattern over the face of the box.
5. Listen for a sharp metallic click inside the box. Once you hear the click, the red LED will turn off immediately, and power will restore to the interior display panel.
6. If the light does not turn off or immediately trips again, stop. This indicates a genuine boiler overheat condition or a failed sensor that requires professional replacement.

Norcold Error Codes & System Thresholds

The table below outlines the primary error codes found on modern Norcold refrigerators, their trigger conditions, operational thresholds, and the correct resolution path.

Common RV Absorption Fridge Failures & Diagnostic Remedies

Refrigerator Fails to Cool on Propane but Works on AC Power

• Root Cause: A clogged burner orifice or misaligned spark igniter electrode. Over time, rust flakes from the chimney flue fall directly into the burner slot, or spiders spin webs inside the burner tube, disrupting the air-to-gas ratio and preventing a clean flame.
• Actionable Fix: Turn off the gas supply. Remove the metal burner shield. Use a can of compressed air to blow out the burner tube and burner slots. Unscrew the brass burner orifice assembly and soak it in isopropyl alcohol for 10 minutes. Blow it dry with compressed air. Warning: Never stick a pin or wire through the brass burner orifice hole, as this will enlarge the opening, destroy the gas flow calibration, and create an extreme fire hazard. Reassemble and adjust the electrode gap to exactly 3/16 inches above the burner slots.

Yellow Powder Residue Around the Burner Flue

• Root Cause: A catastrophic breach in the cooling unit coils. The yellow powder is sodium chromate, an anti-corrosive agent added to the ammonia-water solution. When the steel tubes crack, the pressurized gases escape, leaving the yellow powder residue.
• Actionable Fix: Warning: Immediately shut off the refrigerator and close the LP gas valves. Do not attempt to reset the control board or the recall kit. The ammonia gas is toxic, and operating the heating elements against a dry boiler will cause a structural fire. The cooling unit is non-repairable and must be completely replaced, or the entire refrigerator must be upgraded to a compressor-driven unit.

Recall Box Red Light Trips Intermittently in Wet Weather

• Root Cause: Moisture intrusion into the safety recall housing. Water from driving in heavy rain or washing the RV can penetrate the non-weatherproof casing of the recall kit, causing a short circuit across the sensing contacts.
• Actionable Fix: Open the exterior access panel and use a hair dryer on a low, warm setting to thoroughly dry out the recall box, wiring harnesses, and the boiler stack casing. Once completely dry, perform the magnet reset procedure. Ensure the vent cover louvers are correctly oriented to prevent future rainwater ingestion.

Refrigerator Works Only on AC and Propane is Blocked by "Li op" Error

• Root Cause: The High Temperature Limit Switch (HTS) or its inline wiring harness has developed high electrical resistance, mimicking an overheat event to the control board.
• Actionable Fix: Verify that the boiler is not hot to the touch before proceeding. Use your digital multimeter to check for continuity across the two terminals of the thermal switch mounted on the chimney stack. If the meter reads open loop (OL) when the chimney is cool, the thermal switch is defective and must be replaced. Clean all spade connectors with fine-grit sandpaper to remove surface corrosion that increases electrical resistance.

Frequently Asked Questions

Can I bypass the Norcold recall box permanently if it keeps tripping?

No, you should never permanently bypass the Norcold recall box. The recall kit is a critical safety device designed to shut off power before a ruptured boiler tube can spray highly flammable hydrogen and ammonia onto an active gas flame; bypassing it creates a severe RV fire risk.

Why does my Norcold fridge show "no co" even after leveling the RV?

Once a "no co" error code is saved to the non-volatile memory of the control board, it remains locked even if you correct the physical condition (such as leveling the RV or clearing gas lines). You must manually clear the microprocessor memory using the Pin 2 jumper grounding procedure before the refrigerator will run again.

How do I test if my Norcold thermistor is working properly?

Locate the thermistor clipped to the plastic fins inside the fresh food compartment. Unplug the thermistor from the control board harness and place the sensor tip in a glass of ice water (32 degrees Fahrenheit) for five minutes, then measure its resistance with a multimeter; a healthy thermistor should read approximately 8,000 to 10,000 ohms.

What causes a Norcold optical display to remain blank after resetting?

A blank display after a successful reset indicates a blown 5-amp DC glass fuse on the main control board, a faulty wire harness connection between the exterior power module and the interior eyebrow board, or a complete failure of the 12V DC house battery disconnect switch.

Professional RV Appliance Support Options

If your Norcold refrigerator continues to trip its safety limit switch or fails to cool after a hard reset, the cooling unit may have experienced a internal bypass failure. Contact an authorized RV service center or mobile technician to run a complete system pressure test and restore your appliance safely.