strange instrument behavior

[elk]

I’m investigating an event that happened yesterday just before entering Woods Hole on the way home to Cataumet. The instruments were showing symptoms of a high resistance short. The tach was at 1000 instead of 2000, the water temp was at 100 instead of 165, the voltage was at 10 instead of 13.5 and the low oil pressure light was dimly lit, but the engine was running fine. I turned the engine off and switched the key back and forth, when I put into the glow plug mode everything came back on normally. So I started the engine and all was fine all the way home. Very strange.

I'm wondering if anyone has experienced anything of the sort? I'm thinking it could be the glow plug relay or the key switch.

Thanks,