HOW TO: Dometic refrigerator cooling fan noisy, disconnect the power wire

[John E Davies]

I learned that some Dometic RM2454 fridges have cooling fans located between the upper and lower coils, in an area that is completely inaccessible without removing the unit entirely. Jason in Service told me that they started receiving these units in mid-2017 (mine was delivered in May '17), and that previously there was NO Dometic fan installed. On those units Oliver added their own fan, positioned up high above the upper coils where it was easily reached, and I believe these fans also had an inside On/ Off switch. Yay! Good thinking.

 

Last summer my fan started squealing when the outside air temperature got really high, and there was no way to shut off the nasty noise without killing power to the entire unit. It has no manual switch, rather it is activated by a an inline temp switch that is in the positive wire, near the fan itself. How very inconvenient for the owner.... The squeal went on long into darkness before the outside temp fell enough to shut it off.

 

The Dometic Owners Manual and the Oliver Owners Manual wiring diagrams do NOT show the fan, but the diagram inside the backside of my fridge does; it is located on the far right behind the gas valve. The fan is labelled "Y".

 

 

Here's how to disconnect power from the fan so you don't have to remove the whole unit. it takes about ten minutes if you are slow. If you are careful you don't need to power off the fridge, I did not bother. The electronic control box is covered by a square plastic cover.

 

 

Remove the single Phillips screw at the top, use a magnetic screwdriver if you have one. Don't lose the screw. There are two spring loaded hooks at the 4:00 and 8:00 o'clock positions. Insert a thin flat bladed screwdriver into each slot, lever the handle gently away from the slot while pulling out on the cover. The hooks should release. Remove the cover.

 

 

At the bottom of the circuit board you will see a row of wires. (In the pic they are numbered - that was my idea for when I disconnected them all in a previous project.) The bottom left terminal (J2) has a red 90 degree spade connector which is the fan power wire. Grab it carefully with fingers or a pair of pliers and pull it off the terminal.

 

 

Secure it to the nearby harness with a nylon cable tie.

 

 

You can mark the cover as I did with a silver Sharpie to help you remember how it comes off the next time. Also notice that there are TWO glass fuses (3 amp and 5 amp) which are visible in the pictures above and to the right of the J2 terminal They have translucent rubber covers to keep off moisture. It would be good idea to blow this whole area clean with compressed air if you have it.

 

Reinstall the black cover and go get a beer.

 

Video showing the fan wire with the fan operating. ...

  ... The fan noise is not too bad in this video since it isn't super hot. To get the fan to run, I opened the fridge inside door, turned the temp to Coldest, stuffed some paper towels in the upper vent and waited ten minutes. The fridge coils won't get hot enough with the electric heating element, you have to run the propane flame. Needless to say, it would be smart to keep your paper towels well AWAY from the right side of the coils where the burner exhaust comes up. Do NOT leave this unattended! Please do NOT set fire to your Ollie!

 

You don't actually need to force the fan to run. Disconnecting the red wire will kill it, IF your circuit is like mine. Compare your wiring diagram first!

 

If my fridge cools adequately without the fan I will leave it this way. If it struggles I will remove the two louvered covers on hot days to increase natural airflow. I will be able to test it by mid-summer. Maybe I will have to remove the fridge after all...

 

John Davies

 

Spokane WA

 

 

[Wayfinder]

Am I correct to assume there is a temperature sensor in lower right of picture?  It's not too hot today. Low 90s. 

[John E Davies]

4 hours ago, Wayfinder said:

Am I correct to assume there is a temperature sensor in lower right of picture?  It's not too hot today. Low 90s. 

That definitely looks like one, however it may be this one:

One way you can check is to heat that up with a heat gun (not a hair dryer) and see if the fan kicks on while running on AC power with your switch tuned to ON. I partially blocked off the vent and let the propane burner light off, but I can in no way recommend that risky process! A heat gun is way safer.

Good luck, and thanks very much for posting that pic of the Oliver Installed Fan. PS Your rubber fan mounts have failed, you should see if Oliver can send you some replacements, otherwise it could break loose and flop around, damaging coils and stuff. Plus the red wire needs to have some protection like high temperature split loom, or at least secure it somehow. That is a hot area, I am not sure why it runs that direction.That is where the propane burner exhaust goes upwards. If that is the fan power wire, it could have shorted out and popped the fan fuse. Did you already check it?

John Davies

Spokane WA

[geokeg]

We have hull 178 delivered in Oct. 2016.  It has the manual switch and is a simple circuit, On or Off.  We turn the fan On during hot days  if the refer. needs the help keeping the inside temp where we want it.  You can hear the fan come on and feel the very warm exhaust air coming out of the top exterior vent. The fan gets turned Off when the exhaust air out of the top vent gets back to a normal range.

[topgun2]

I'm in the same boat as George and with hull # 117 am a bit closer to Wayfinder's hull #.  I think that I remember reading about the temperature (in the fridge compartment) that initiates the fan but my Owner's Manual is presently in my Ollie which is in its storage yard.  In about a week I'll be at the storage yard and will take a look to see if I can find that reading.  However, in the meantime, when I have the fridge fan switch in the "on" position, the fan certainly come on well before external temps are in the 90's and does not shut off until the external temps get at least in the low 70's.

Bill

[Ray and Susan Huff]

Does opening the awning to shade the wall outside the fridge help some?

 

[SeaDawg]

17 hours ago, Ray and Susan Huff said:

Does opening the awning to shade the wall outside the fridge help some?

 

Yes, it does. As does parking in the shade. If you are cooler, your fridge is cooler, and doesn't have to work as hard .

Bug screens are a double edged blade, as well. Even larger mesh screen cuts airflow. But, keeps the mud daubers and critters out, which cause more significant issues. 

In our earliest 2008/2009 Ollies, there was no fan, neither from Oliver nor Dometic. Some peoole installed small 12 v fans in the upper vent area to exhaust the air over the coils more efficiently.  That really helped, especially those folks who camped in the heat. Another reason we prefer moderate elevation, shade of the forest, and shoulder season camping.

[mossemi]

On 6/19/2021 at 4:12 PM, Wayfinder said:

Am I correct to assume there is a temperature sensor in lower right of picture?  It's not too hot today. Low 90s. 

You are correct, that is the temperature switch.

 

Mossey

[John E Davies]

Update, I have had no issues with cooling in hot weather.

John Davies

Spokane WA