Reverse lights not working

Try replacing or checking first the switch for the revers light.

Back-up light switch.

Inspect the wire for damage.

Checked all fuses and changed the neutral position switch. Still not working. Now what ?

Put my test light on the switch plug with the shifter in reverse and ignition on, and not hot.

Keep tracing back to the rear end. Have you checked the bulb socket, and see if the power is back to that point? Behind the bulb socket the wiring should run to a plugin. Start checking from there also.

Check voltage at the wiring plugs under bed, it might be disconnected or damaged

Seems there is no power to the plug at the neutral position switch which I replaced that switch from the dealer, With the shifter in reverse and ignition on.

Transmission was rebuilt and came back with no working reverse lights

Had a similar issue, 123_456789. Just got a 2000 Nissan Frontier V6 XE. One of the issues is no working reverse lights. The other issue is that the a/c sporadically blows cold, and then cool air. For the reverse lights issue, hubby was wondering if the transmission had been rebuilt, and the people rebuilding the transmission forgot to re-hook up the switch. We talked to the owner, but the transmission has not been rebuilt yet. And it wasn't the fuze for the back-up lights, that was still working. The issue ended up being the back-up switch itself. The switch itself is still fine, but over the years the switch filled up with transmission fluid and contact was being lost. He cleaned out the switch and voila, it works now.