by Philip » Fri Feb 22, 2019 6:47 am
By power supply I have to assume you mean the power train control module (PCM).
Keep all ground connections clean and tight. The battery is your surge protector. Bad grounds is what would cause surges when you turn items on.
93 W350 Club/cab w/duals, buckets & console, B&W flatbed, G56, 6 spd, 3:07 rears, gages, HX40/16, 4" exhaust, 6X.018 sticks, rear air ride suspension