My fuel gauge registers full all the way through about half tank. When it reads half I'm just about empty. I know it's not the gauge as the gauge in my new Dakota Digital dash acts the same way as the factory gauge I just replaced.

Does the "arm" inside the tank simply stop rising up and down or is the problem usually electrical in nature? I'm going to replace it regardless, but I'm just curious.

Thanks.

Does the "arm" inside the tank simply stop rising up and down or is the problem usually electrical in nature? I'm going to replace it regardless, but I'm just curious.
Fuel Gauges work by resistance. The lower the resistance, the lower the gauge will read. First check wiring. Look for the gauge connection (a 18g tan wire) near the tank. Normally its in the trunk (not sure where on a El Camino) Disconnect that wire, with the key on, ground it to a good bare metal ground, the gauge should read empty. If it doesn't, you have a wiring problem, if it does, the problem is downstream of where the connection is (wiring or sender)

thx