codes P0128, P0116 & P0117. I have replaced the coolant temp sensor, wires, etc.

My sensor has 2 wires leading from the little cap. Not sure about the 3 or 4 you're talking about. Ok, here's what happened. Last year I had an overheating issue and I replaced the coolant temp sensor, thermostat and fluid. The A/C had quit a couple months earlier. I had read online that the sensor has a lot to do with the A/C compressor functioning. Anyway, after fixing overheating problem I tried turning on the air. Holy crap. it worked, very excited. Approx. 4 months down the road had to replace my clutch. When the mechanic dropped the transmission in the process, he literally dropped the transmission and yanked out the wires from the sensor. No more reading for temp, engine light is on and no A/C. Had the wires soldered back into the cap and all was good for about a month. Since then, what I mean by intermittently is that temp will read out and A/C works for anywhere from 1 day to a few weeks and then suddenly no read out, engine light on and no A/C for however long again. When we check the codes I get what I posted earlier. So we replaced the wires, replaced the pigtail and replaced the sensor again. We reset the computer twice as well. There is a short somewhere, but where do I look? What else can I check?

Look at the ECU. Follow the wires, pulling them apart from the wiring harness as you go, and find the farthest place from the ECU that gets voltage. There is not a better way to do it unless you have the diagram for the pins in the ECU. However, I don't understand why you are the one repairing it, and not the tech that broke it... Also, if you are getting power to the sensor, but no signal from the sensor, replace the sensor.... again.