Help I have a 90 k1500 was converted to carb before I got it has optional temp amp and oil pressure gauges under dash my problem is my all fuel gauge shows full when empty and speedometer is stuck on 45 I don't know if they took the computer out or not do this cluster operate thru the computer any help or thoughts please tell me

 

Yes the computer needs to be in. No reason to take it out for a carb swap. It's rare for a computer to go bad in the gmt400's but possible.

 

With the speedometer stuck on 45, I would say it is more likely a problem with the speedometer itself. With no signal or not moving it should go to 0. The fuel gauge may be as simple as a bad sending unit or a bad ground. Always check the simple things before going into more complicated repairs which may not be necessary.