The second, and most recent, sounds very similar to your issue. You may just need a new solenoid, but in my case the fix actually turned out to be rewiring a new ground wire to the solenoid. I am not sure what happened to the original ground because tracing it through the system was not easy and everything behind the LPG breaker looked OK. You could probably test if this is the issue by simply adding a new ground wire and touching it to the steering pedestal or something and see if the circuit is completed and the solenoid switches. Once I figured out this was the issue the hardest thing was crawling behind the locker to re-wire. I just attached the ground to a ground that was in the lazarette. Probably not the best solution, but it worked.