98 24V cummins alternator external sensor
 

My 98 24v alternator quit but tests good.Charges if hooked to positive wire from battery.
The hot from the switch doesn't turn on [or from ecm]. Was told sensor in ecm is bad.
Got an external sensor to by pass the one in ecm.There a vague instructions and say not to hook old wiring up again to side post of alternator which were the hot and ground.Do i need to run a hot wire from switch? or will that continue charging?
Need help on how to install or which wire should be hot.
Thanks:s: