i have a olderhot tub sunwave by aquatherm the back psi switch rotted out and leaked all in my control pannel i replaced the switch stoped the leak but now when it is on the heater keeps turning off then right back on it will keep doing that also the pump is wierd you can hear the motor running the whole time but the water comming out of the jets is pulsing like it will blow water out then no water then blow more water out the whole time the moter is running

Welcome to the forums.

It was tough reading without any punctuation, but it sounds like you just need your water level is alittle too low from that initial leak. I'd suggest making sure it has enough water.

The surging of the pump is caused when the jet pump sucks in air. As it looses pressure, the pressure switch circuit opens, and turn off the heater. As soon as the pump regains it's prime and begins pushing water, the pressure switch closes, and this cycle repeats endlessly.

Add water, clean your filter[s], and check the filter area for anything that might obstruct water flow.