water temp gauge not working

I have a 355 f1 and after I did the major service the water temp gauge is not working. After warm up the little red light starts to fade in to bright red any suggestions.
I did install the gold connector kit from Mr Helms and it might be possible I switched two wires not sure how to diagnose though because I do not understand the temp gauge wiring logic. Any help would be appreciated, thanks Grant

 

I think that the problem may have occurred on the wires from the oil water heat exchanger can some tell me what the difference is between the temperature sensor and the temperature transmitter on this heat exchanger vs the temp sensor on the radiator and what their purposes are. Thanks again fellows

 

I think the temperature sensor is the sensor for oil temp actually that tells the sd1 your oil rad fan is supposed to turn on and the temp transmitter is the one that sends a signal to the dash but I am not sure. Any comments ?

 

At this point until I have the temp thing fixed I have not been able to drive the car much so I can not answer about the gold kit entirely, however what I do know is the engine idle seems much smoother. I will update once I use the car more.

 

The temp transmitter(such as the name suggests) transmits signal to dash gauge and the wires were backwards from when I installed the gold supremo kit. This was the first plug that was done and after that I made sure markings did not rub off. Thanks for everyone help. Car failed smog yesterday but after I get that sorted will update on new thread about gold supremo kit. Grant