My old 32Sb had a bad bathroom GFI. Same issue as you are having. I replaced it - and never had another issue with electrical.
Roselyn and Darrell
2007.5 Silverado LT/EFI Live Tuned Duramax/6Spd Allison/Banks Ram Air with Super Scoop/Edge CTS Gauges/Air Lift Load Lifter 5000 Ultimate Air Springs
2014 335ss Cruiser Provincial