I fixed the overheating problem on my 1190 Ergo seat using a 20 watt DC-to-DC converter (Digikey part number 102-3216-ND). I could not get the seat's circuitry to work reliably for voltages much below 12 volts, so I set the voltage to 12.5 volts to provide a bit of margin. Regulating down the voltage applied to the seat's heating element from the bike's normal 13.8 volts to 12.5 volts, reduces the heating power by a factor of (13.8*13.8)/(12.5*12.5) = 1.22. That 22% power reduction makes the seat comfortably warm rather than burning hot. If you would like more info, send me a PM.