short?

when i drive my 88 s10 at night the gauge panel flashes like it is getting no power.The radio flashes then resets the fuel gauge goes to empty. And when im driving the my sub's will not even work but once i turn the car off and on to accessorie the subs will start to hit.But if i push up on the dash right behind the blinker switch the power is all there.

Pull the cluster out and clean/tighten the contacts on the back.