no reading temp, oil and fuel level gauges?
 

i just started helping my friends son get his first fb going, he bought it not running, it would almost fire and stall, and flood. so with in 2 hours i corrected several vacuum system issues,and found the shutter valve wired closed with a properly functioning shutter valve, and some wiring and she fired right up. but only have a reading on the voltage gauge, and tach. no oil pressure (put in a mechanical to check and it has pressure), coolant temp, and fuel gauges are all dead, and its got a buzzer with key in the ignition, that goes away when the car starts, kinda like the coolant level buzzer but no coolant light on, and coolant is full. Ive checked fuses, tested sensor resistance, and wire continuity, WTF do i do next?????
any ideas???? should i be looking behind the gauge cluster or is this gonna be somewhere else?
car is completely stock 85 gs
the previous owner wired in a factory fuel pump direct to the battery, as the factory connector is supposedly dead(i gonna get that figured out next time im there)

Make sure you have a GOOD ground from engine to firewall.

good grounds, no gauges
 

Engine to firewall ground is good, made extra ground for instrument cluster, still no reading on oil, fuel, and temp gauges. What else causes this? Bad cluster?