I have a 79 dodge power wagon. Sometimes the truck would start normally and other times there would not even be power to turn on the head lights. I would mess with the battery connections and make sure things are plugged in and usually it would start up. This last time it would do nothing at all. There is power going to the starter because when you touch the two connections at the starter they spark. But I'm guessing that it is not completing the circuit. If you have any suggestions please let me know.

I have a 79 dodge power wagon. Sometimes the truck would start normally and other times there would not even be power to turn on the head lights. I would mess with the battery connections and make sure things are plugged in and usually it would start up. This last time it would do nothing at all. There is power going to the starter because when you touch the two connections at the starter they spark. But I'm guessing that it is not completing the circuit. If you have any suggestions please let me know.
Check both ends of both battery cables to make certain they are clean and tight. Checking for sparking at one point won't always reveal most problems. A voltage-drop test should be done to see if corrosion or poor connections are causing this problem. Also, have the battery properly load tested to determine if it is sufficient for your vehicle.

Follow your negative cable and make sure it has a good ground also make sure the wires are all tight even on the starter

The cables could also have corrosion up inside from the ends causing a problem. Then again, it could be the ignition, or neutral safety switch.