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Old 09-15-2010, 10:26 AM   #1
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A little run down on why I did this mod.

My fridge is the Dometic that the temp cant be adjusted, no slide or knob to change the temp inside the fridge. Moving the Thermistor up or down didnt do anything for the temp. The lowest my fridge would go is 40 degrees. Thats too warm for me to feel comfortable with.



So I searched the net and found that Dinosaur boards has a box with a potentiometer in it with two plug ends coming off it into the thermistor on the power control board and then plug the thermistor into it. You plug it in and are able to adjust the temp by tricking the Thermistor into believing the fridge is warmer than it is. You turn the knob one way for warmer the other for colder. The only thing is with the Dinosaur part,it has to sit in the outside area where the back of your fridge is accessed from, not a good spot to be able to adjust the temp of the fridge, its also expensixe at around $40.00It isa simple thing to make yourself with parts from Radio Shack. So thats what I did. Here is a link to the potentiometer http://www.radioshack.com/product/in...ductId=2062287and this one is for the knob http://www.radioshack.com/product/in...ductId=3014503



You getthe 100K linear potentiometer from Radio shack, and a knob to fit it, price for all this is about $5.00 pus tax. You need some wire too, I used solid core wire it has less resistance, and it is stiffer than regular stranded wire,and it was sitting around my shop. You need about 6-8 ft of it, with two wires total, to run I used Red and Black. Shrink tubing also is helpful or electrical tape.



First thing is remove your eyebrow board above the fridge, it comes off easily, just kind of twist it up and away from the fridge. Under it is a bunch of wires that go down to the back of the fridge. Mine had 2 holes one was plugged with expandable foam the other was open, use this hole. This hole runs to the back of the fridge and should have 2 wires running into it. There is plenty of room for more wire. (this is why I use solid core wire about 22 gauge, it is stiff enough to go through the hole, also twist the 6 ft of solid core together with a helper and a slow speed drill)



Now take a wire coat hanger and straighten it and bend a little hook in one end, make a very small hook, your going to put the hanger into the hole and push because there is some kind of putty or silicone on the backside of the fridge to keep critters out. You want to break a hole large enough to put your wire through, you wont be able to see it but you can work it through once you use the coat hanger to push a hole in the silicone to get your wires to the back of the fridge. Push the wires through and after it stops go outside to the back of the fridge and use a mirror and flashlight so you can see the wires at the top of the fridge.



I used a thin piece of wood, about 1/4" thick with a nail drove into the end of it and bent overto grab the wires and pull them down. This took the most time as the nail will grab the wire but will slip alot, but keep at it and you will get the wire to come down. A helper will make this easier if they can feed the wire through the hole from the inside while you pull from outside.



Once the wire is pulled down cut the thermistor wires and twist one of them back together and then twist in one of the two wires you just pulled down, then do the same for the other thermistor wire. Tape or shrink tube them. I soldered my wires it is a better connection but twisting them and taping them will be fine too.



Now go back inside and drill a 5/16" hole on your eyebrow board somewhere. I put mine to the left of the controls that are already there. There is alot of room over on that side.



Now there is a small nub sticking out on one side of the potentiometer, file or grind it off you wont need it on there and it will get in the way of installing it in the eyebrow board. Also cut off about 1 1/4" off the shaft of the potentiometer using a hack saw, the shaft is too long and wont look good sticking out so far when installed with the knob in the eyebrow board.Install the potentiometer with the 3 electrodes straight up.Solder the wires to the middle and right electrode, that is while looking at it from the front side with theshaft closer to you. Solderone wire to each electrode. You wont use the left electrode. (when you use the right and middle electrode, when you turn the potentiometer to the left it will make the fridge colder, to the right warmer. If you use the left electrode and the middle electrode it will be opposite, right turn will be colder and left will be hotter)



You can fill the hole you pushed the wires through with silicone to keep the critters out.



Now istall the knob and put it all back together and you now have an insidetemp control for your fridge.

Edited by: fixit5561
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Old 09-15-2010, 12:17 PM   #2
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give this a try everyone seems to have good results
http://cgi.ebay.com/ebaymotors/DOMET...Q5fAccessories


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Old 09-15-2010, 04:49 PM   #3
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Quote:
Originally Posted by gsxr
give this a try everyone seems to have good results
http://cgi.ebay.com/ebaymotors/DOMET...Q5fAccessories






Already have one of them bought from ebay from that seller. I have had it since the spring and it didnt work for me. It does keep the fins from icing up when it is blowing the fans towards the fins, and having to be defrosted more often but thats just what I had noticed. It didnt cool my fridge any lower than 40 degrees as I stated above. I have always had it running while testing the temp of the fridge.

I even modified it and turned the fans around (emailed with the guy who makes and sells them, he recommended turning the fans around)and it still didnt cool it more, it just moved the air around more is all I found. But thats with my situation everybodies is different. Also I still am keeping it because now I dont have to buy batteries anymore to have a fan recirculate the air in the fridge.



I have been testing the potentiometer and it works great. I got my fridge down to 29 degrees in a few hours and the potentiometer isnt even turned all the way down. It seems the ideal place on the dial of the potentiometer is right about the center. If I go past center to the left about 1/8th turn it goes way down to 29 degrees with alot of room to move it more. Im happy with it so far, and it works great.



I read where others used resistors to fool the thermistor, and had them on their rv for years. So a potentiometer is just an adjustable resistor so it works for me because I can adjust the temp of the fridge now.
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Old 09-23-2010, 03:09 AM   #4
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This is a GREAT mod. My wife always questioned the refrigerator running in the high 30's. I had already added and auxillary fan to pull heat up and out of the rear compartment and exhaust to the outside. After I read aboutyour mod I picked up supplies and finished this on Tuesday of this week. I'm just adjusting and checking temps at different setting. Your directions were right on also. Fairly simple to complete. Thanks
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Old 09-23-2010, 04:37 AM   #5
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Thanks HCG!



Yes I have the outside fan also to try to cool down the fridge coils in back, that along with the fans inside still didnt do the trick, but now it doesnt matter I can dial it down when it needs it. I kep mine at 33 degrees right now. It stays within 1 degree each way too. (I have a temp gauge that is digital and gives me the highest and lowest temps the fridge runs at)
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Old 08-07-2014, 11:52 AM   #6
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Thanks 5561, after searching many forums regarding Dometic fridges inability to hold a temp that won't spoil my food on a trip I found your "fix". I'm happy to say IT WORKS !
I purchased the pot and knob this morning and did the mod, as the day time temps are climbing to the upper 80s the fridge temp is falling into the 30s. I'll have to play with the pot to get the setting I want but for now the fridge temp is falling instead of rising ..
Thanks again for your posting.
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