ARP (Fridge defend) install 2005 Winnebago Vectra

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An absorption refrigerator can get very hot while cooling the content especially when the RV is uneven. The manufacturers added some recall devices to it but they only shut off the fridge when it is extremely and dangerously hot, then this device locks the fridge preventing it from starting again.  A better solution provided by is the  “Fridge Defend”. This device will shut down the fridge at a much safer temperature and will start it again when it has cooled down. In addition, you can order this device with a fan controller and fans to put behind the vents. These fans cool the back of the fridge, making it work more efficiently (better cooling) and safer. To optimize the cooling of the inside they have fans available to circulate the air and prevent condensation.

ARP Control solves problems with the refrigerator whereas the Norcold control solves a legal issue Documentation used in this article;

  • General Install Guide v5.x
  • ARP User Guide v5.x
  • Troubleshooting Guide v5.x
  • Ancillary Graphical User Instructions v5.x

Some facts:

The ARP will switch off your fridge when the boiler temperature reaches 482 Fahrenheit while the recall device that is on most fridges will switch off at a whopping 800 Fahrenheit

WEBINAR with the ARP engineer
ARP Reference card (PDF)
NORCOLD 1200/1201 service manual

Using this article is totally your own responsibility!

We ordered the v5.1 ARP Fridge Protection Control with Fan Controller and 2 Fans, we already have inside fridge fans. (#4 KIT for side vents fridge in a slide)


The first thing I did after receiving my order was labeling the wires for easy install and documentation;

Be very careful pulling off wires you might brake brittle connections.
The fastest way to do the install is first to decide where to connect the boiler sensor and glue the sensor to the clip then attach it to the boiler tube. I put the sensor about 6 inches above the electric heater tubes and turned it to the right.
After you labeled the ARP wires, decide the gender of the connectors by checking the connection points.
For example; the YELLOW ARP wire needs to be connected to the fridge controller this needs probably a female connector. When you know that, you can crimp that connector on the ARP Yellow wire. Do this for each connection. It will get you an overview of what has to be done and saves a lot of time while you actually connect the ARP. For ground connections (GREEN) you probably need some splicers when you also have vent fans.
When done with the connectors move on to the actual install.

From left to right: (Numbers in brackets are referred to the schematic below)



POWER-IN RED Disconnect the BLUE wire from the fridge controller [4] and connect the power in RED wire of the ARP [2] to this BLUE wire. The other end will stay on the recall device [3].
POWER OUT YELLOW This YELLOW wire goes to the fridge controller [4], (12 vDC) where the BLUE wire was removed.
This is the boiler [5] temperature sensor wiring, connect to the sensor with clip using the provided connectors.
GROUND GREEN Attach to a GREEN ground wire you can find on the fridge. Use splicers for the FANS
FAN CONTROL BLUE Add RED fan wire of each fan to this BLUE ARP [3] wire (The BLACK wire of each fan goes to ground GREEN)
Temperature wire, use a clamp to attach to a coil. (Clamp just the eyelet)


Fan temperature sensor fastened with a hose clamp


Remove the fridge controller protective cover (you need to remove some wiring and the icemaker water valve too, take a picture before you do!)

Punch two very small holes in the cover and mount the ARP on the top left using the screws in your package. Tape some small cardboard pieces on the inside on the screw ends so nothing can damage inside the controller cover. I know you are curious and want to know what’s behind the controller cover. (SEE BOTTOM OF PAGE)

ARP mounted and controller cover reinstalled:

Note: This picture was taken before any wire connection was changed or connected. (Blue wire (12 volts DC) on the controller board is still there)

SCHEMATIC: I’m using the Wiring Scheme Number 1 from the above link.

  1. RV 12 volts DC power (YELLOW wire on the Vectra)
  2. ARP
  3. Recall device
  4. Fridge controller
  5. Boiler assembly

Wiring Scheme Number 1

Description from;

(1) Starting at the RV, the RV delivers the power to run the fridge and its controls. Please note that two wires will enter the cooling unit compartment, one power, and the other ground. Because the color of the power wires varies by RV manufacture it is up to the installer to determine the correct wire color for the power and ground.
In our Vectra the positive 12 volts wires are YELLOW and the ground wire is GREEN.

(2) The ARP will interrupt the power to the RV fridge in order to turn on and off the cooling unit heat source. The ARP can be wired anywhere along the +12VDC power wire.

(3) The Norcold recall is shown with only the +12VDC wires. The +12VDC wires are the only wires that the ARP Control will connect with on the Norcold recall box. Thus, the power supply, the Norcold recall box, and the ARP are wired in series with the power supply to the Norcold fridge controller (4).

(4) The Norcold fridge controller receives the +12VDC power from the RV power supply (1) via the ARP yellow wire. We show the Norcold fridge controller ground wire because this is a good place to ground the ARP control. We do not recommend grounding the ARP control at the same location as the Norcold recall (3).

(5) In order to make the wiring complete we show the cooling unit boiler assembly. Please note that the insulation around the boiler assembly is not shown. The ARP temperature sensor is clipped onto the boiler tube. The boiler tube is easy to identify because the boiler tube has the electric heater holders welded directly to it. The flue tube is usually behind the boiler tube on all Norcold fridges.

Recall device wiring;
All wires of the recall device stay connected like they are.
You can use the green wire from the recall device to split and add the ARP ground cable (green)
The BLUE wire on the right goes to the fridge controller board and needs to be removed from the controller board, NOT from the recall device! Then you need to connect that end to the RED power-in wire from the ARP

NOTE: This recall device is the Norcold 637360 Temp Monitor Control and will still be active in the wiring. It is a legal requirement from the NHTSA (National Highway Traffic Safety Administration)

ARP Boiler sensor install

First, glue the sensor into the clip with superglue (See the General instruction guide for the correct way) and then connect the two sensor wires with the provide connectors to the WHITE/PURPLE  boiler temp wire.

I use a sharp knife to slice open a vertical part of the boiler tube and clipped the sensor on the tube according to the general instruction guide. I used aluminum AC tape to repair the cut.

The image shows the temperature sensor install alignment on the boiler tube. In this image, the boiler tube is black, the red arrow points at the flue tube which is red. The easy way to detect the boiler tube is by the fact that the electric heater mounts are welded to the boiler tube. Please note that the black arrow shows the direction the clip is attached, this makes it easy to slide the sensor away from the flue tube once attached. Also in this figure, the yellow dashed line shows the next to top absorber coil. The sensor should be no higher than this coil and not any lower than one inch above the electric heater elements.


Lower vent FAN installation


Upper vent FAN installation (not sure yet if this is the right position)



I’m planning on using these male and female connectors for the fans behind the side vents to minimize the extra cable I would need in case I want to remove the vents.
10 male and 10 female connectors.

HOW TO WIRE THE FANS        (RED on the plus (+) sign and BLACK on the minus (-) sign)
Attach a MALE connector to each fan
Attach a FEMALE connector to the wire at the top FAN and route the wire down to the bottom vent
(Secure the wire that comes from the top fan) and attach a MALE connector tot that wire ending behind the lower vent.
Add two FEMALE connectors to the FAN CONTROL (BLUE wire from ARP)  both on the plus (+) side of the connector. You can use extra cable to split the wire in two leads or use a wire splicer.
Add a ground connection (From a GREEN wire) to the negative (-) side of each FEMALE connector. You can use extra cable to splice the wire in two leads or use a wire splicer.

WHY this way you might ask?
By using male/female connectors I do not need to have extra long wires on the upper or lower fans when I need to remove the vets. Make sure you put the male and female connector on the correct end of the wires as described above otherwise a disconnected male connector can touch a metal part of the RV and can cause a fuse to trip.

Examples of a wire splicers

Wire splicers

Use a splicer like this one to have to wires out for the upper and lower FAN shown is the BLUE fan control. Each YELLOW wire (12 volts DC Winnebago style) goes to the RED wire of the fan.

Fan on/off indicators;

To easily check, if the fans are running I added a LED light for each fan that will indicate that the fans indeed are running.


After the install, you need to test the ARP by following the user manual that will guide you through the procedures.

Picture of the fridge controller board, I know you were curious 🙂

(I disconnected the 120 volts wire from the bottom left)

Note the two fuses, glass fuse (F3) on the 120 volts side in the lower left (5 or 8 amp), and the 5 amp 12 volts orange fuse in the middle.

The BLUE (12vDC) wire on the bottom right needs to be removed, the other end is connected to the recall device. The  YELLOW wire from the ARP will be plugged in instead. The BLUE removed wire needs to be connected to the RED power-in wire.

Video from 2017 by the engineer of ARP with question and answer session highly recommended when you want more explanation about your fridge;


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PDF download

NORCOLD 1200/1201 service manual

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