gauge cluster problem

[oldschool18]

My uncle just bought a 79 K10 and I think he might have a ground problem but I havent looked at it yet. He says his gauges Oil, temp ect. the needles seem to be moving backwards I'm guessing there spinning upside down and he said when he turns on the one turnsignal his highbeam light flashes and when he put the other turnsignal on the other turnsignal flashes and his gas gauge is not working. I gave him an extra ribbon circut for the back of the cluster and it did the same thing. I thought he might have a ground problem but wasnt sure if they changed plugs on the cluster and someone did a swap before they sold it or if anyone had a problem like this.....thanks