fist thing its a 83 z28 and the cluster is not fully in yet but the cable is connected to it because i cant pull the thing out and if i give it a push in the gas gauge moves (i think its right). the rest dont work. if i am driveing and give it gas the gas gauge moves up like its the speed omiter, and it will flicker with when the signal it on. also when i put on the lights no dash lights come on includeing the shifter and heater and the stock system display goes blank but music still plays. one more thing when i turn the head light nop to full some place under the dash makes the continus buzing sound.
any ideas????????????

 

Having the cluster on the connectors loosely will cause quite a few electrical gremlins to show themselves through the gauges. Making sure the tabs on the harness plug have a good arch to them (so they contact the printed board contacts good) and are clean can help eliminate some mystery problems. That and solidly mounting the cluster.
Check the INST 5A fuse. the gauge, HVAC, console and radio lights are powered by the headlight switch. If the fuse is good, the switch is bad.
Not a clue really. Where, roughly, is the sound comming from ? Turning the headlight *** fully on completes the ground to the dome/courtesy lights, it shouldn't be affecting anything else that I can think of.