model 470 sun dance jaccuzzi

[constanta]

I have a 4 lines on the spa lcd showing that a "WATCHDOG" message is active and will not allow the pumps to come on.i noticed that if I reset the breaker it will work for a while.now it trips it instantly and if I disconnect the J8 connector from the lcd panel the jaccuzzi stays on with other fault codes such as SC1 and SC3 for open or shorted sensor for the freeze line,flow switch and temperature sensor. I puled out one wire out of each terminal for all of the sensors trying to figure out if any of them is causing the problem. it did not work but the same 12 cavity connector has a black wire that jumps rom one cavity to another diagonally across and with everything connected I have only one message on the lcd panel. the pumps still don't work which is expected but my breaker works well. my question is what is the black jumper wire do in the J8 connector and why does it trip the breaker almost instantly. thank you for your attention and help to my dilemma.