Posted: June 06 2007 at 08:19 | IP Logged

Sounds to me like you may have a ground problem somewhere.  This not a problem found only on boats, I've seen cars do it as well.  My thought is to trace your ground circuit, clean up any/all ground connections, and check for any possible shorts going to ground.  these problems can be a real Bi&*% to find, good luck

Paul

Posted: June 07 2007 at 08:47 | IP Logged

I believe that any auto parts store worth thier salt should be able to check for a bad coil.  I generally try to start simple and then work my way up.  Its cheaper than the reverse.  How about the light switch itself?  Check under the dash for corossion, or questionable connections. See what the ground wires look like up there.  Follow that hot and ground wire around looking for something that doesn't look up to par.  A multimeter can sometimes be of a great help in checking for continuity.  One good method is to eliminate things that work.  If you can get ahold of some kind of schematic it will prove invaluable.  Like I said before, These problems s*^k

Good Luck

Paul