It has a full 12v on both sides. I havent checked the grounds for the pump. Are there any inline fuses in the wiring for the pump? if so were would I find them.Are you getting a full 12v on both sides of the inertia switch? There should be 12v in and 12v out. If youre getting 12v in but only 6v out, replace the switch. If you have 12v out, check the wiring from the pump. Check for any breaks in the wiring or corrosion in the connections. Dont forget the grounds.