What you have installed there is an adjustable intake air temp sensor. The bass knob type setup in the cab is just an adjustable potentiometer that is wired into the intake air temp sensor wiring to control the voltage that the PCM sees. I have used some of these setups in the past. By adjusting the potentiometer and controlling the voltage that the PCM sees, the idea is to make the PCM think that the air charge is cooler when it is entering the engine so it will make the fuel mixture richer and therefore make more power.
The issue I would have with mine is what is possibly happening to you right now. The adjustable setup has probably been turned too far one way and has the voltage either too high or too low and the PCM is setting a corresponding DTC. Also, the adjustable potentiometer may have failed internally and is no longer able to provide the correct voltage to the PCM. Either way something needs to be done. If the voltage goes too high or too low the PCM detects this and sets a DTC.
You can connect a scan tool and monitor the IAT voltage while turning the knob and setting the voltage to a point that is low enough to show the PCM that the air is cooler entering the engine and then mark the adjustable knob so you know where to turn it to if you or a friend turns the knob.
If you want to eliminate this setup from your truck, cut the electrical tape off of the harness and remove whatever is installed into the wiring harness and remove the adjustable setup in the cab.