D-1tub

hello, a newbe to this forum but not a newbe to the spa. have a 96 dimension 1 ( californian). just recently the gfci tripped. flipped it back on immediately tripped again. unplugged heater, flo switch, the pumps, still trips. put in just a plain 40 amp breaker and the tub works but the flo 1 is displayed and don't think the heater is working. filters are clean, dffuser is clean and a new flo switch last fall, any IDEAS????????