X2
Check the wiring at the connecters at the alternator with the key off. Then turn the key on.There should be one wire that is hot only with the key on. That should be the wire that turns on the alternator. Start the engine and see if the wire is still hot. If it is the alternator should be charging. If there is no hot wire then you need to find a wiring schematic to find out which wire should be the excitation wire. When you find it you can hot wire it to test the alternator output. Good luck on it.