Power for Fan inside Fridge

joetab1977 · 06-20-2019, 07:08 PM

A total novice here, but I can follow directions. If I choose to power my fan using the power going to the refrigerator light, as this guy does (

https://www.youtube.com/watch?v=IO3EppMBfvE&t=3s

), how do I know which wire to go into? Do use a multimeter to find out where the 12 V constant is?

I have a black line and a red line going to my light. Pictured here: https://drive.google.com/file/d/1FcP...ew?usp=sharing .

Thanks,
Joe

DavidBo · 06-20-2019, 07:26 PM

Here's how I wired mine:

The fan I got came with a little terminal to tap off the existing connection. You can see that at the top of the switch. On my fridge that's the hot wire going to the switch, that way the fan will run with the door closed. Verifying that with a multimeter or test light is a good idea.
My fan needs a ground, that's the other wire on the terminal to the left. I think your fan grounds to the fins so you'll only have the one wire to worry about. You don't need the tapper, just strip about 1/2 inch of wire and fold it over the male terminal, then push the female terminal on to hold the wire in place. The switch pops out of the bracket which makes this much easier.
On a side note, those stock bulbs get very hot, that's why I went with an LED replacement. Make sure the wires don't touch the glass just in case.
Hope this helps!

joetab1977 · 06-20-2019, 07:38 PM

Thanks David! This is very helpful.

What fan did you install?

Thanks,
Joe

DavidBo · 06-20-2019, 07:50 PM

Quote:

Originally Posted by joetab1977

What fan did you install?

This bad boy!

I got it from Ebay, I think it's the same folks that made your fan. The switches control the fans individually, there's also some pretty cool LED lights that I usually leave off.
There is a noticeable improvement, especially when it comes to initial cool-down time. Now I can switch the fridge on at night and it's usually plenty cold in the morning, before it could take over a day.
Let us know how it came out!

LJS1211 · 06-21-2019, 02:26 PM

I have a similar fan and I just ran my wires straight down the drain tube and connected it to the power source at the back of the refrigerator. Works great and definitely makes a difference in this Texas heat.

Paulie1138 · 06-22-2019, 09:11 AM

The cooling on my 12cf ‘fridge was marginal at best. Made some mods as follows.
1. Added the ‘snip the tip’ thermistor. Holds the set point very well. My slider never worked right.
2. My ‘fridge is in a slide, so no roof vent. Added 3 whisper quiet 12 volt computer fans into the thermostat near the heat exchanger in the back side of the fridge so I get air movement, and the fans only run as needed.
3. Added a small fan below the cooling fins near the water drip tray inside the fridge itself. Saved space, have plenty of air flow. Added a micro-relay to shut off the fan when the fridge light goes on. (Means the door is open, not wanting the air to circulate then.

With those mods, I can easily maintain 36 in the fridge, and always below 18 degrees in the freezer, even in the Arizona summer heat-without having to mess with any temp settings.

SlowrideHD · 06-22-2019, 09:31 AM

I did very similar to davidbo. I tapped into the hot wire that powers the fridge light. It is always hot because the door switch for the fridge light breaks the neutral (or ground). I used a small fan from an old inverter that no longer worked and made the fan bracket from some thin aluminum strips that I bought at Tractor Supply. This keeps my fan about a half inch off the top surface of my fridge where I mounted it and it blows all the time the fridge power is on. It is a very small fan but circulates the air perfectly in the fridge. Everything is cold and no more frosted up cooling fins. I grounded the fan by drilling a tiny hole through the left end cooling fin with a 90° drill adaptor and using a screw to secure the wire. I used a good epoxy to glue my little fan bracket to the top of the fridge cabinet. It has been working great for a couple years now.

I also replaced the fridge evaporator/condenser fan with two super quiet ball bearing computer case fans. Now I never can hear when those fans run. I can not hear the little inverter fan run that I used inside either.

SlowrideHD · 06-22-2019, 12:30 PM

I'll eventually hide the wires but they don't interfere with anything.

DavidBo · 06-22-2019, 01:34 PM

Quote:

Originally Posted by Paulie1138

Added a micro-relay to shut off the fan when the fridge light goes on. (Means the door is open, not wanting the air to circulate then.

I've been wanting to do something like that with my setup; it makes sense because the fans will simply blow the cold air out when the door is open.
Could you tell me what kind of relay you used? I'd assume it was one of the generic mini-relays so popular with modern cars, but you might have found something better. Any particular recommendations on the wiring?
Thanks for the suggestion, it's also another excuse to go gadget-happy with my trailer. I'm bad about that!

Paulie1138 · 06-22-2019, 09:20 PM

I do not have the PN readily available. The relay I used was not one of the automotive types, but much smaller. I think the contacts are rated for 1 or 2 amps. My fan draws something like .08 amps. Besides the 2 wires for the coil, has 3 active connections, one common, one N/O, one N/C. Coil activates when door is open when the light goes on. With the door closed, relay is in the ‘rest’ position. I have the fan tied across the common and N/C position. When the door activates the light, the coil switches those contacts into an open position, dropping power to the fan.

In this manner, the relay is not consuming power with the door closed. The relay is energized with the power to ground via the light turning on. I will post if I can find a part number. I stuffed my relay inside the siding of the fridge behind the light.

DavidBo · 06-22-2019, 10:10 PM

Quote:

Originally Posted by Paulie1138

In this manner, the relay is not consuming power with the door closed. The relay is energized with the power to ground via the light turning on. I will post if I can find a part number. I stuffed my relay inside the siding of the fridge behind the light.

That's what I assumed. I found a normally-closed relay on Amazon that should do the trick. Now I have to brush up on my old electrical training, I can't remember if the relay is wired before or after the load from the control circuit. I'll figure it out, at least I know I have half a chance of getting it right.
Thanks again!

Iwannacamp · 06-22-2019, 10:51 PM

My fan is very low amperage. Change to an led light and the amps would prolly be lower than the incandescent bulb alone. On my fridge the master switch at the top also turns the light off... so I leave the fan on. One could easily use a test light to figure which one is hot.

Paulie1138 · 06-23-2019, 09:45 AM

DavidBo, while not the exact same as the one I used, this will work depending on how much current your fan setup draws. just use a set of contacts that are not energized while the light is on. I used the light as a power source to trip the coil on the relay when the door is open/light on. Coil gets energized, causing the fan to lose power.

Here is one similar:
https://www.amazon.com/uxcell-Mount-...gateway&sr=8-2

I removed the light and installed a high power LED. More light in the fridge, also less heat from the lamp.

If you boondock often, these are great mods to save a bit of battery current. I see no need for the fan to run with the door open, but a fan really helps to circulate the air inside the fridge.

DavidBo · 06-23-2019, 04:03 PM

Quote:

Originally Posted by Paulie1138

I removed the light and installed a high power LED. More light in the fridge, also less heat from the lamp.

If you boondock often, these are great mods to save a bit of battery current. I see no need for the fan to run with the door open, but a fan really helps to circulate the air inside the fridge.

That looks like a good candidate, thanks!
I was looking at some automotive style normally-closed relays, but those handle like 30-40 amps, which is serious overkill. These smaller relays are for PC boards but that's easy to work around. Since my fans have a separate ground wire, I might have the relay control that which will simplify the wiring. I never thought that little bit of electronics training I got in college would come in so handy!
You aren't kidding about the heat that little factory bulb puts out. It was on for only a few seconds when I tried to remove it and it was already too hot to touch.
To the original poster, I hope we didn't hijack your thread. One thing I really like about this forum, you're guaranteed to get more information than you asked for!

Paulie1138 · 06-23-2019, 05:11 PM

So true about too much information. I have also gotten a ton of information and great ideas from this site.

Thanks for the reminder, DavidBo. To the OP, no intent to hijack!

joetab1977 · 06-26-2019, 10:10 PM

DavidBo, is this the piece that pops off? Circled in my pic: https://drive.google.com/file/d/1-0T...ew?usp=sharing .

Thanks for your help,
Joe

DavidBo · 06-26-2019, 11:22 PM

Quote:

Originally Posted by Paulie1138

Thanks for the reminder, DavidBo. To the OP, no intent to hijack!

Actually I was referring to myself, I've probably hijacked more threads than I've started myself!

DavidBo · 06-26-2019, 11:34 PM

Quote:

Originally Posted by joetab1977

DavidBo, is this the piece that pops off? Circled in my pic: https://drive.google.com/file/d/1-0T...ew?usp=sharing .

Thanks for your help,
Joe

That looks like the connector for the wiring to the switch, it should come off the terminal. The switch itself can be removed from the bracket by squeezing the tabs on the side and pulling forward, that gives you a bit more room to play around. Just be sure to route any wires through the hole in the bracket before attaching to the switch so it will fit back in, don't ask me how I know this.

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