[77newell]

My 77 had the Ford rheostat and did the same thing Steve was just reporting. In my case if I wiggled the switch knob just right the lights would flicker on and off thus proving that the rheostat was the problem. I removed the switch and was able to bend the arm that rides on the rheostat windings and I also used a points file to remove any crud on the contacts and it worked just fine after that. There is a high amp fuse on the switch but I doubt it is for the dash lights.

Regarding Yachts problem. If as you say all those circuits are fed through the ignition switch it could be that switch. I had one of those fail without warning. The hardest part of the replacement was keeping track of what wires went to which terminal on the switch. The test to see if it is the switch is whether there is the full 12 volts getting to one of the positive terminals on one of the uses of the current.