Hello all, I own a 93-94 Sundance Calypso 400 series spa with a controller board part number : 12-6600-031

My problem is, the heat led light on the top console keeps turning off.... Once in awhile, starting and stopping the electricity, there is a click when I turn the heat control knob, then it just goes out again.

I am at a loss, can anyone please help with possible ares to look for the problem....??