I have a 1977 Silverado C10 that I have redone from the ground up, I have a small problem, I plunked and Olds 403 with a T400 into it recently and there is a wire (redish or brownish) running from the fuel tank switch (about mid frame) that I have no idea where it goes, along with this the fuel guage is out of wack, showing way past full, Im a bit baffled, I think it runs to a power source but I really dont want to wire it in and have something burn up, any help would be fantastic.
Thanks
Al

 

When you disconnect the fuel gauge wire, it goes all the way to full or farther, when it is grounded it will go to empty.
assuming you have 2 tanks that lonely wire may go to the guage in the dash, which is usually a brownish colored wire from what i remember.
If the gauge is way past full generally that means there is no ground at all to the sending unit itself, or the gauge wire is disconnected - thats ruling out any faulty parts.

 

Thanks, I did in fact figure out the wire issue, and it did match up to one that goes in through the fire wall, had to replace a sending unit, so alls good!
Al