2005 ford escape 4wd v6 3.0 problem over charging over 18 to 20 volts

Hi guys my name is jesse im a mobil mechanic
I have a customer with a 2005 ford escape 4wd v6 3.0 problem is that overcharges
It already has a new PCM and a new alternator, any ideas ? Thank you

Voltage drop test with engine running (loaded circuit), the Black/Yellow wire at the generator and battery positive. Should read less than half a volt. Or if you don't want to run the car with an overcharging problem, unplug generator harness and insert test light connected to ground, to female terminal of the black yellow wire. Test light should be of sufficient amperage to properly load this circuit. After all it is fuse protected by a 15A fuse. However if this high resistance is substantial, any load will be very evident.

New alternator from ford or aftermarket? These fords you can unplug the connector on them and snap throttle a few times should put the alternator at a default charging rate of 13.5 with alternator unplugged. Also it could be a sulfates battery and is trying to charge it back up. Battery new? Have one to substitute for testing?

It’s a Ford Smart Charge system.
Scope brown and white for control and grey and orange for monitoring.

Both signals will be digital square waves. But the control should not be constant. The monitor will.