How to Install a STC-1000 Temp Controller on a Chest Freezer (Drunk Morons Included)

Let me start off by saying that I had a really hard time finding the right way to do this, mainly because my tiny brain doesn’t allow for such complexity, but also because there isn’t that many great recourses or instructions online. But once the correct diagrams finally were found it wasn’t as hard as I thought to get it to work (I also had help from a friend who knew more about this stuff than I did, yet was equally as drunk during installation).

I have two chest freezers, and the first temp controller I installed differently than the above diagram, yet it worked and I have no idea how. We didn’t use a jumper and just put the white and black power cord wires in directly into 1 and 2, and the chest freezer compression cord wires directly into 7 and 8. But of course doing it that way with my newer Haier chest freezer did not work at all. This took some beers and some online scavenging to find instructions on what to do.

The simple way (untested by me):

I have not tried this brand or this way, but something like the A419 temp controller looks like would work. From what I gathered you can just plug your chest freezer into it and it works without rewiring unless you want to change it from a cooling to a heating option. That can be a downside, but if you don’t need a heating element then it’s worth a shot. There is also this if you have more money than me, which does have a heating element option built in.

The more complicated way (tested by me):


I decided to use the STC-1000 at the time I did this, and for those who want to go this route, it’s not too complicated to install. The STC-1000 is the most popular brand (it does read only in Celsius, but I printed off a conversion sheet to Fahrenheit and have it taped next to the controller for reference), granted it’s not like there are a whole lot of different kinds out there.

The benefit to this temp controller is you can have the option for a heating element once you install it without having to rewire it every time you want to change what it does. I don’t use a heating element (I’ve seen people use a light bulb in a can, but a heating pad could work too I’m guessing) because for 8 months out of the year I don’t need it with my garage being either in the 90s or 70s during those months, but late October to late February I could use a heating element sometimes. I have been using a space heater turned on intermittent if I need a little more heat, which I’d rather not do to be honest. This could be the year of the heating element!

The only tools needed are a small flathead screw driver and a wire cutter to cut the plastic insulation back so the exposed wire can fit in the wire nuts and the little ports on the temp controller. If you want to be a fool like me you can just use box cutter to cut the wires, but I highly advise against that. The small screw driver is to tighten the wires into the ports of the temp controller.

The only true physical danger is of course getting electrocuted, so double check and make sure the chest freezer is unplugged when you go to do this…and of course we did not have it unplugged at one point during this and my buddy got zapped. Two fucking drunk morons hard at work. If you don’t want to chop up the power cord that came with the chest freezer, then you can get a power cord from a hardware store and use that, but you will have to make sure you ground the chest freezer and I don’t know how to do that exactly.

Instead of describing exactly how to install the controller step by step, I figured the best way is to just show diagrams as there really isn’t a sequence. The photo at the very top is the same description as directly below, except a wire nut is not needed to connect the black wire from the power cord to 1, 5, and 7 if you don’t have/want a heating element. Just as is shown in the diagram at the top, I just used a small piece of wire (jumper) to connect 7 to 1, and the black wire from the power cord also went into 1 (they both fit…that’s what she said?…sigh).

wiringstc1000 heating

The diagram directly above is easier to navigate than the hand drawn one. Neither of the diagrams are mine, but the one directly above did not originally have the heating element instructions, so I drew in what I think might work (it did have the grounding warning, but both my chest freezers already had grounding). The heating instructions I drew in very well may not be right…it may work with the heating element wires going directly into 5 and 6 as the sensor wires go directly into 3 and 4, so if you know an electrician or are handy with this kind of shit, then do what works if what I drew for that isn’t right. I just copied how the “cord to fridge” was done. There is also this insanity I have no patience for, but I will say it would be really nice to have a custom made outlet for heating and for cooling without dismantling the chest freezer.

If you have questions about this, I probably won’t be able to answer them as I just did exactly as the diagrams showed (without a heating element installed as I mentioned). If it won’t work, yet you felt like you installed it correctly, then there may be something wrong with the chest freezer or a connection is off somehow. However, if my tiny brain could figure this out then you should be fine!

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