help with gas gauge.

[low~n~blue]

I have a 1993 ford ranger splash standard cab, 5 speed manual and 2 wd. The problem I have is my fuel gauge. It will go all the way up when started then come down and then randomly rise again, and come down again. The gauge was working perfectly until one night at the gas station, i had a mishap and the door got damaged, long story short, i had to unplug the "dinger" because the door wouldn't shut. Since then I have had the truck repaired and and the plugged the dinger back in. The gauge stopped working that night when I had to unplug it. Worked when i pulled into the station and didn't when i went to pull away. I was assuming the gauge shared a connection with the dinger and figured it may be a bad contact since it stayed unplugged for a couple weeks but i don't know. Any idea's what it could be? anyone know of a wiring diagram thats available? I don't think its the sending unit because of coincidence with unplugging the dinger but it could be. any help is appreciated, thanks!