The power valve motors draw their current from the PGM in the seat hump, and excess current draw is usually the best way to kill your PGM.

Have you checked all the connections are free of corrosion and properly seated?

Might be worth whipping the top off the PGm and checking it for signs of overheating - burnt smell or darkening of the rubber coating. If the valves rotate once I'd gues it was fine though.

Any good with a multi meter? can you connect it inline and check the current draw when it works and again when it doesn't?
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