Wire routing isn't right obviously. I believe the original truck's wiring had one lead near the alt/gen output and one lead near the battery pos lead, at or near the horn relay. Both wires need to be connected to B+, as in "hot all the time" circuits, not ignition switched. One wire must be close to the alt/gen output wire and the other wire must be closer to the battery positive, such as at the horn relay. On my '63 I have an '03 5.3L installed, so I rewired the whole truck and don't remember exacly how the original set-up was, but the amp gauge will function properly if you connect the leads as described above. If you get them backwards, you'll know it because the amp gauge will deflect to the discharge side when the alt is charging. If this occurs, simply reverse the leads to the gauge. On my truck I have the alternator sense wire connected directly to the alt output stud and the battery load sense wire connected to a battery fed fuse in the IP fuse block. Remember, both wires must be connected to B+ circuits to avoid the feedback issue that was not allowing you to shut the engine off.
