blower motor ground wire

electrical newbie.....i have a 1994 jeep cherokee. the blower motor has 2 wires a green and a tan one. anyone know which one is the ground? or how do you find out which is what? thanks.

Hopefully you have a multimeter.
What is the issue with the blower motor?

dark green seems to be the power feed from the controls to tan should be the ground.

the body wiring is showing black as the ground. but after the connector to the actual fan unit itself could be anything.

Yep, multimeter.

Continuity (Ohms) check from the two pins on the connector the blower plugs into back to battery negative or chassis ground will identify which one is which.

That being said, most multi-wire automotive electrical connectors I have encountered have some clip/lug/etc. on it to ensure it can only be plugged into it's mate one way and cannot be plugged in "backwards". Is there a concern that your motor might be wired backwards?