74 Thing fuel gauge HELP

there a little pulsing unit sumwhere, but for the life of me i cant remember, its common fault with age tho. someone will know the part with a link(i have seen it in past) but i have drinked a lot :-/

I have a '74 Thing and the fuel gauge has pretty much quit working. It does work on occasions, but only shows half a tank when it's Full. Otherwise, the gauge is usually pegged on E. I have had the tank sender out and just to look at it, it appears OK. I traced the wire back to where it is connected to the gauge...terminal is clean and tight. I guess it's time to replace the sender or the gauge, but I hate to guess which to try first. I"m sure there is a way to check the sending unit with a volt meter, I just don't know quite what to check for. Any suggestions are greatly appreciated. Thanks! Eric snipped-for-privacy@psci.net