​​​​​​Picked up my father's 2003 Tribute for my kids when he was getting rid of it. He knew the reverse lights had stopped working but since it wasn't the bulbs he had opted to not have it repaired.

2003 Tribute ES, 3L 6 cyc DOHC
AUTOMATIC Trans so no stand-alone backup sensor, just neutral safety switch

Bulbs: good. Even tried new bulbs
Fuse #6 10A (3rd down on right column in panel) tests fine on multimeter
Replaced the Neutral position safety switch with a new one from AutoZone but that didn't solve it.
Dashboard shows the appropriate gears as selected; runs great in all gears including reverse.
While I had it apart to install the Neutral Safety switch I cleaned up the contact points on the ground point attached to top of transmission ( engine mount bracket, technically) as my understanding is that it's a ground-switched circuit so wanted to eliminate a bad ground contact.

At the left receptacle w engine running and trans in park I'm getting ~12.8 v on Org/Yel and ~13.2v on Blk/Pink. With engine running and Trans in reverse I'm still seeing similar voltages from each.

Why isn't this thing dropping to ground in reverse even with a brand new switch? What else should I check?

 

Quick update (yes, it's 3AM locally)

I pulled the airflow, battery tray, and engine mount again and disconnected the plug from the neutral position safety switch.

Tested continuity from terminal in the switch's plug with the black wire (presumably the ground) to a few areas:
* This ground point bolted to the radiator/thermostat support bracket & engine mount bracket bolted to transmission. Continuity passes

Ground wire attached to the bracket that in turn is bolted down with the engine mount bracket (driver's side)
*To Transmission. Continuity passes
* To the negative battery wire clamp. Continuity passes
*To the ground point on the body behind the airflow where negative battery wire is stripped to make connection at ground point. Continuity passes with touching the bare spot on wire a d the plate it was clamped to but not the bolt holding it to frame. Bolt and washer top were very rusty. Hit it up with some rust cutter gel and brushed it up a bit. Now continuity passes including at other threaded/unpainted holes in the body under the hood.



Continuity also exists between all those points with each other as well so I don't see a bad ground path between the ground in the neutral pos safety switch and the battery post. I'm lost as to where else to look

 

After all the continuity checking I plugged the switch back in, connected the battery, put key in run and trans in reverse. Across the wires at the bulb socket now I'm getting hot on yellow/red and ~2v on the blk/pinkz and about 5.2v across the wires?

Any help you all can provide in the AM is greatly appreciated!