electric problem its a weird one

[spencer_41188]

ok i got a 87 chevy r30 cac, the otherday i was driving and it started raining go to turn in the wipers and nothing so i played with the switch i turn on the wipers and my gas guage peggs on e and my dash lights turn on soand the dash turn signals turn on there real dim i turn them off i get home wondering wtf is going on i turn on the parking lights and the samething happions fuel peggs and no dash light but the turn signals come on on the dash only real bright so i pull the dash off and start pulling apart the wire harnes and taping it back as i inspect of corse it was a firetruck and they just love to add there goodies i made a fue repairs with the trusty wire diagram by my side i test it everythings good to go get it all put togeather and everything is fine and dandy then it comes back im starting to think water has gotten to the fuseblock maybe pulling it out blow it off with the air gun and lather it up with some dielectric grease any input would be great help