I have a 2005 290 Open that acted strangely today! When I turned on the main power circuit breaker, the warning horn came on while the ignition was off. My oil pressure went to 40 psi without the engine running. I started the engine and ran it a second to build oil pressure after an oil change and then could not shut it down by turning off the ignition switch. I had to turn off the main DC breaker for the engine (not the main battery switch). I suspect the ignition switch is bad, but wanted to run this past the group. Any thoughts?