troubleshooting fuel sender problem

can anyone walk me through how a fuel sender is wired on a 63 mercury? I'm getting pretty tired of having to guess how much gas i have. I bought a new sending unit a while back, hooked it up and got nothing. I know there is only one wire going to the thing but dont really know how it works. any info is greatly appreciated. -Joeks

 

Sometimes you need to ground the sending unit with a wire from one of the mounting bolts to the frame. It does ground through the tank BUT...

 

Ok Is there a ground wire going from the body of the gage to a ground on the body or frame? You have to have a complete circuit to make it work.
Have you checked the wire to the sending unit to see that you are actually getting voltage there when the key is turned on?
The sender has a resister in it that changes resistance when the float arm moves up or down changing the reading on the gage.
You can check the sending unit by pulling it out of the tank and hooking an ohm meter to it and checking resistance through the arc of the float when you move it up an down. You should be able to check the operation of the gage by hooking the sender up and hooking a ground wire to the housing of it and then work the float arm through it's arc while having someone read the gage in the car to see if it corrisponds to where you have the float positioned.

 

would a 63 ford have that neat voltage reducer on the dash? You need power to the gage itself, in addition to having a working sender. And grounds at the sender and dash unit are important.

Usually you can check the dash unit by grounding the sender wire...disconnect the wire from the sender...if the needle moves from one end of the gage to the other when you ground the wire, then the gage is probably working ok and probably getting power and ground.

 

63 has a votage reg in the dash. pull the wire at the tank. see if your getting power. start there. should be a yellow/ white wire. the gauge gets power from the voltage reg in the dash.

 

thanks for the responces guys. took the sending unit out and there are several cracks in the float, hopefully thats my only problem. anybody know where i can get one of these...fast?