2005 Avalanche Intermittant Seat Heat

[MrDel]

My 2005 Avalanche has issues with the drivers side only seat heat cycling through the heat ranges at random. This occurs ONLY when rainy or damp. If there has been significant rain I can count on it happening. The seat heat will simply bounce around the 4 positions (3,2,1,off). If has stopped raining and it is sunny it will dry out and eventually stop altogether. As it dries the cycling lessens. I have taken it to the dealer 3 times and they changed the lower seat element which had no effect. I took a shot at the door switch but $170 later it had no effect either. It's a safety concern as I get real tired of pushing the buttons to turn it off all the time. I have seen a few posts long ago with this syndrome but both dead ended with no solution. Any help greatly appreciated.