I am not surprised by their response. They are telling me I have a bad ground. I don't think this is the case but I am finding the previous owner did some questionable things to the vehicle. First thing according to the Classic Parts technician, I should only get needle movement when I turn the ignition switch on. Right now, as soon as I hook the battery up the needle buries regardless of the position of the switch. This tells me the feed to the gauge is hot all the time, bypassing the ignition switch. They also told me the ground wire I have from the sending unit to the back of the cab might not be good. They told me because of the rubber bushings on the cab mounts I might have to run a ground to the frame. I will trace the wires one more time to make sure the feed from the sending unit is wired through the ignition switch and I have a good ground. He also told me a bad ground will allow the needle to swing way pass the full mark the same as disconnecting the sending unit completely because the needle will bury when there is an open circuit. However, I will test it one more time with an extra ground clipped to the frame. He also told after verifying the ground, if I ground the sending unit the gauge should drop to empty. I will have an update tomorrow.
Last edited by dgrinnan; 06/27/2016 6:32 PM.
