So out of the blue, my PoTC no longer registers ball trough switch 3.

I did the following:

1. On the mpu, verified that I can trigger the switch 3 pin (which is the white-orange wire) with the green-red wire, switch registers fine in test mode.
2. On the trough, I used my dvm on the switch and it works just like the others.
3. At the connector from the switch to the wiring harness, I verified continuity from the white orange at the switch to the white-orange on both sides of the connector.
4. There is *no* continuity from the connector side of the white-orange to the backbox white-orange at the connector. I verified that ball trough 4 wire (white-red) *does* have continuity from the connector to the mpu connector (and works fine obviously). I looked under the playfield and it appears that all the ball trough wires make a direct run from the connector at the ball trough right to the connector at the mpu.

I don't see any obvious pinching or breaks of the white-orange. All the other ball trough switches and optos work fine

From the above, I am deducing that:

1. MPU switch matrix is fine.
2. Physical switch is fine
3. the wiring switch to connector at harness, and harness to male-to-male to other harness is fine.
4. Orange-white wire must be broken somewhere, right? I did try testing the wire itself by displacing insulation short of the actual idc connectors and there is no continuity.

Is my only option to run a new wire?

thanks

Ok, easier fix than I imagined. I forgot the cardinal rule -- always start with the simple stuff first. I went to the switch test and went through that column of switches, one by one, and found the issue, LTG -- It was a wire broken off from the switch. 30 seconds of preheating the soldering iron, $0.003 of solder, and 4 seconds on the switch and boom, fixed and all good. Oh forgot to mention the two hours agonizing over it! lol