Alternator working intermittently?

[casman86]

My alternator is sometimes working, sometimes not, with no apparent pattern. I thought replacing it would be the solution but it still has the same problem. I've checked almost everything. Could this be caused by the wires that run from the alt to ecu? That's the only other thing I can think of to check. If anyone knows how that system works please chime in. What voltage should those wires be seeing with the ignition turned on?

[Klits562]

make sure the grounds r tight n clean check belt tension n make sure all the connections r tight

[casman86]

Bump. Does anyone know what voltage the wiring harness plug on the alt should be reading? I still have this problem. The alternator is working about 3/4 of the time.