fuel tank sending unit

I can't seem to find my wiring diagrams. 1968 fuel tank under seat. Can anyone tell me where the wires go. I see one terminal coming out of the sending unit, should there be more? Where should the ground wire go? I put a body on plus the wires were a total mess before I began so I am starting with a tank, sending unit, and guage that is all.

Josh

 

Sorry, forget it. I found the info on a previous post. Center post on sending unit to guage, ground a mounting screw to a good ground. In my case not to the body its fiberglass. Any further instructions/wisdom?

Josh

 

Wait a minute. If the center post goes to the guage and the tank gets grounded , where does the power come from? Does the guage have power all the time, if so where does that come from?

Josh

 

The ground for the gauge is through the sending unit to ground. I think you mean "does the sending unit have power all the time?" - yes. The resistance of the sending unit changes with tanlk level, and that changes the voltage at the sending unit terminal (and at the gauge).

 

Sending units have always scared me. Even if it just a ground wire, you sure want everything done right.

 

Yeah, but where does the guage get its power? I don't think mine is hooked up to anything- no wires in back.

Josh

 

I think there is a metal bus bar on the back of the gauge that supplies + voltage for the gauges. That't how my 59 looks anyway, hope this helps.

 

Ok here we go. I wired everything up the best way I could. Now I checked for continuity between a sending unit attachment screw and a known good ground- It is grounded. I hooked up the center of the sender to the terminal on back of guage. I hooked bus bar which seems to supply power to the water temp and fuel guages up to the ignition side of the ignition switch. Now- no reading on the guage but when I turn on power I can here something moving or buzzing or something in the tank. I checked between the terminals on the back of the guage. No continuity between term. No Ohm (resistance) reading showing up between them. Should there be? Does anyone know what is in there that makes the needle move? I think I need a new guage what do you think?

Josh

 

Anyone have any experience with this? I looked on the "How stuff works" web site. There is a bi-metal strip in there that changes shape when electricity passes through. Since I get no resistance reading I'm assuming it is bad.
Josh

 

This page may help with the wiring http://www.jeeptech.com/electrical/gauges/
We have a member here that has a page with excellent info, I think he calls his Jeep Binky, I have it downloaded and if you need it sent to an email file let me know.

 

Here's Stan's page that Mike refered to--lots of good info there.

http://home.comcast.net/~sday77/

 

Thanks for the great info guys! I don't know where I'd be without all the great help I get here.

Josh