I don't have my machine or manual in front of me, but in switch test, just depress the switch on the other shooters, it should register, then do the same with shooter 2.

I've almost never had a switch issue that wasn't a broken wire at the switch, a diode on a switch or a loose connection on the idc connect going to the board.
Sometimes the switches get flaky and need to be replaced, but they usually work after a couple presses.

So I looked in the online manual (maybe i don't have one for this NBA, but this is the second time i've owned it).

If you look at the switch location pic 2-42 2-43, it looks like you may be talking about defender 2.

Then you take that information goto 2-48 on the chart. Go up and and left and J-206 and j-208 are the connectors.
So find J206 on the cpu (skinny tall board) and reseat and press the wires in.
IDC connectors are awful, almost every machine i've owned has been some level of project and so far every machine has had an IDC problem.

On the switch itself, i usually clip out the diode (take a pic for the direction and lugs it goes back on), check the switch contacts for continuity when depressed, then check the diode while it's out, one way on diode test should give you a reading, the other direction should be nothing.
Regardless, once i pull a diode i replace it (i just like to know if it's bad).

I'm not an expert by any means, but i've probably fixed 50 switches over the years without spending any money (other than diodes, but they are like $2 for 100).

Your manual is here:

https://www.ipdb.org/files/4023/Bally_1997_NBA_Fastbreak_Operations_Manual_Final_no_schematics.pdf

On PDF page 104 is the parts diagram for the pass-assembly (2 and 3).

The first thing I look for when a switch isn't working is to see if there is trash blocking the ball from resting on the switch!

So check to see that there isn't a screw, a piece of plastic, a fragment of a piece of rubber in the place where the ball rests.

The next thing I do is to go into switch edges test. I take a ball, and put it in the pass-assembly-2 ball area. It should make a noise, and the little box associated with switch 67 should light up, and stay on as long as the ball is resting on the switch.

If the switch doesn't register, lift the playfield, and look at the pass-assembly-2 assembly. There is a small black microswitch, and it has a wiring harness (two wires) coming off of it. I don't have a machine in front of me, but I believe that the wiring harness goes to a two-pin plug. Check to see that the wires are connected to the switch (not broken off), that the plug isn't unplugged, and that the wires all seem to be in good order.

Black microswitches fail. Not often, but often enough.

You could buy something like this:

https://www.pinballlife.com/microswitch-with-diode.html

The blade assembly pops off of the old switch and onto the new one.

You'll have to solder the wires to the new switch.

Let us know what you find!

Most playfield parts on the bottom come out within minutes if not seconds.
Mainly with a 1/4 nut driver.
When switches start to go bad, sometimes they work, sometimes they don't.
There are also times the metal just needs to be bent again so it depresses the switch.

Personally, i'd remove that assembly and replace the switch and diode.
The wiring underneath the playfield most likely is good or it isn't since it's soldered, if it's a wiring issue usually a wire is broken off or it's at the board connection.