89 dodge alt and reg test??

Hi, I have a 89 dodge pickup 5.2 auto. The alt isnt charging, I beleive the regulator is bad.

But first i wanna check the alt.

do I grnd one of the field wires? I dont remeber?

also if the alt is good, then the regulator must be bad, but its in the ECU (air box)

How can i bypass it using the older mopar regulator.

thanks

Don