97 s10 pickup 4.3 sending unit

97 s10 pickup 4.3 sending unit. purple to gauge black/white wire? my black/white wire has 5v at conector sending unit does your sending unit get volts. my ohms are correct on sending unit. nothing on gauge empty. when i shut the key off from on gauge goes to 1/4 tank. even when sending unit not connected goes to 1/4 with truck key out.can i test my cluster some how for my fuel gauge