84 electricel freak out

[84beast305]

hey guys i really need some help here my truck is a 84 gmc 1500 the other day we were hualen my bike to the shop and had to slam the brakes on when someone ran a light after that my ebrake light came on but a few miles later went off ... that night i was driven home and my dash lights went off i also noticed me fuel gage had droped to zero u turn the head light off and it reads like normail u turn the turn signal on and it pulses my wipers also quit at the same time i installed a new fuel tank right before this happend my fuel gage aslo quits randomly but when it rains or u drive through water it majicly starts to work ... its my daily driver so any advice is appreciated thanks...

[Pontiac1976]

Check for gounds straps. tank to sending unit, motor to body, body to frame. also check the Power wire on the sending unit is good.
then let us know how things go.