Troubleshooting 110v 10A Digital Temperature Controller

[Blackicep8ntball]

My brother and I are converting a vintage GE chest freezer to a keezer/kegerator and ran into some trouble hooking up the digital temperature controller.

We purchased a "Fahrenheit 110V 10A LED Temperature Controller Temp Sensor -58~194 Thermostat US" (looks like this:

). This is our second time installing one of these temperature controllers - the first time was in a brand-new chest freezer, where it works with no problems. However, when we installed the new controller to the vintage freezer, it starts the compressor for a fraction of a second before turning it back off; then, after a few seconds, it does the same thing again, and again. The LED screen lights up too (we set it to 39 degrees ferenheit) but it gives a funky reading when it turns the compressor back off. Any ideas what might be the problem?

I'm no electrician, but in case it's helpful to someone who is - the freezer runs off of a 1/4 hp motor, and the label says "FL Amps 3.5-5.5." Glad to provide any additional info if it'll be helpful!

Thanks.