Engine Starts and quits immediately afterwards

I will look into the kill switch to confirm if that is a problem. Thanks!

I have a open bow 1995 GT40 HO Ski Nautique. When I try and start the engine It runs for about a second or two then quits immediately afterwards. I feel my problem with it is I'm not getting power from my Ignition switch purple wire down to my EEC relay when I turn the Ignition to on (pin 85 on the EEC relay). I have taken the instrument panel off to access the 10 point connector and measured for continuity from the 10 point connector down to pin 85 on the EEC system relay. I am baffled that I have an open circuit between the two points and I'm thinking I have a bad diode. the wiring diagram that I have shows that a purple wire goes from the ignition switch through A 10 point connector one diode and then to the EEC point 85 on the relay. I don't know much about diodes except that it allows current to flow one way but if it fails does it fail open or closed to allow current to flow. And I would love to test this diode to figure if it may be the problem if I knew where to look to find it. Any suggestions or thoughts on the matter would be great! Thanks Shane