Muzbomb, have you or your son seen an over temp light or display since you installed the deluxe gauge? I found one and installed it in my 2010 M6, then went through every setting available and found a 00 input for engine temp. the settings i found to be working are MPH, RPM, MAX RPM, ODO/KPH, Trip 1, Trip 2, Hours and Voltage. All other ( hidden ) inputs 1 through 8 all read as 00.
The lights on the left side are High Beam, Low Oil and Over Temp. The High Beam works properly, I assume the Low Oil light will work properly as I believe that sensor is a toggle sensor.
I am not real convinced the High Temp light will work properly as that will be pending the type of sensor for high temp. If the ecu reads the temp sensor and the ecu sends a toggle on/off code to the gauge it might work. If the sensor only reads the real temp and sends signals to the gauge directly and the gauge turns on the light then it may not function properly.
So the question is have you seen an over temp light or a display on the deluxe gauge since installed?