recheck your work and mkae sure all your wires were connected and covered with shrink tubing. then check yoru battery and charging system.

I did use the shrink tubes and thought I connected every thing well I don't know how old the battery is but have had truck for two years if the fan isn't on and my voltage is still fluctuating could it be still wire connection?

it cold be but you may have damaged something else and to give an answer that is why i said check bettery, but you may also check the crging system wires, maybe one of those were melted as well. there is a fusible link near the power dist center that goes to alternator and that cold have been burnt or damaged to protect alternator. it has a blk/gry wire going to it with an 8 guage wire, it may have partially burnt through meaning it wold do your volts like you are saying it is. they are available at auto parts.you might also check fuse 2 &11 in power dist box and fuse 14 in junction block under dash. Also make sure battery terminals are clean.