12V Electronic Temperature Controller Programmable -50 to 110 Degree Celsius Heating/Cooling Thermostat Control Switch Module NTC Waterproof Sensor Probe Dual Color LED Display Monitor (2 Pieces)

Just use the default option, these are very accurate, change the settings is tricky because of how small they are, but I find the default option to be fine. They work to control a small relay and no problem with the connection. Just follow the instructions. Used to turn a 12vdc fan on when the temperature probe sensor is 2° above the set point. Works great.

Great little temperature gauges. I installed this into a car audio amp rack. I wired up two 30mm fans to it. One to take in fresh air and cool off the amp, and one to pull the air out of the amp space. I chose this method because my amp is going to enclosed behind 3/4 plexiglass. The wiring was a little confusing at first, but after a second look i discovered that all 12v power wires (battery , and both fans ) go into connection 1 on the back. 12v ground from the battery goes into connection 2 on the back. A bridge wire is used to go from connection 2to connection 3 on the back and then both fans negative (black wires ) go into connection 4 in the back. This allows the connection to be made and activate the fans when the set temperature is exceeded. I have included a video to show you the operation, i hope this helps anyone who purchases this product.I have noticed that my led lights on my enclosures and amp rack dim when the temperature is exceeded causing the fans to come on. I think this might be an issue on my end because i couldn’t get the 14 gauge wire i was using to connect to the distribution block (on the back of my amp rack) to go into the connections on the back of the temperature gauge so i spliced in some 20 gauge. I think this is causing the dimming.

This thermostat is very basic but it works very well. Mine didn't come with wiring directions but now they show the diagram on the product description on AMAZON (but it still isn't very clear). One thing they don't explain is why there is a jumper between the ground inputs, as depicted on the top portion of the wiring diagram. What I found is that if you attach a switch (on/off basic switch) between the negative input and negative jumper input (right next to it), you can use that to keep the fan or heater element from turning on and still have the thermometer on and showing the temperature. Why would you want this? In my case, I don't want the fan or heater to turn on while I adjust the thermostat to the temperature I want it to turn on. I can just look at the red dot on the thermostat to see if it turns on or off while not pushing power to the fan or heating element. This will also keep the fan or heater from turning on accidentally and running your batteries down.I have this installed in three different areas in my coach.1. Electricity bay to keep the inverter and other electronics cool. It runs an exhaust fan.2. Battery bay to keep the lithium batteries at the appropriate operating temperature. It runs an exhaust fan and heating element.3. Water bay to keep the water pump from freezing in the winter. It runs a heating element.

Hook-up connections were supplied with the unit. Had to search online for info on setting parameters. They work great. I set one up as a control for a 120v bulb in the fridge I keep on the back porch. The lamp turns on to create a little heat if it gets close to freezing so by beverages don't freeze and burst. The second one turns on a 12v rope light in a plastic tote. It keeps my sourdough starter and dough at 73degrees when the rest of the house is about 66 at night. I may get more of these if I can figure out where they would come in handy.

No wiring instructions included. Had to look at the original Amazon add to verify. Parameters were easy to figure out even without instructions. Hooked up to what would be considered a 6" computer type fan to assist in venting an enclosed area. It didn't work at all. Ended up wiring the fan direct. I am sure the fan will prematurely wear out. Looking for an alternative or another product.

The controller appears to work fine when used with a low amperage load but gets stuck repeatedly resetting when used with a higher amperage load.I purchased this controller to use in combination with a 150W ceramic heater. The electrical load of the heater is 12.5A at 12V which is well below this temperature controller's supposed maximum load of 20A at 14V. I first tried running the heater's ground directly through the controller. When the controller would close the relay, the controller would immediately turn off causing the relay to open. It would then immediately reboot and close the relay again, which would cause it to turn off again. The temperature controller stays stuck in this loop indefinitely.The controller does correctly and accurately control the heater fan (<0.5A at 12V), so the issue appears to be with running decent sized loads.I was able to get the temperature controller to control my 150W heater by connecting it to the gate of a RFP30N06LE N-Channel MOSFET and using the MOSFET to control the heater. See the attached photo of my wiring schematic.Programming the controller wasn't hard... once I found a manual. You can find it by searching for "Ketotek KTF0091". I've attached a photo of the one-page manual.I'm giving this 3 start because technically it works as intended. However, its actual load capability is substantially less that what is stated, no manual was provided, and programming it would be impossible without a manual.