1991 Dodge Dakota Back up lights

Turn the ignition switch to "run". Crawl underneath and unplug the backup lamp switch from the transmission. Use a stretched-out paper clip, cotter pin, or piece of wire to jump the two terminals in the connector. If you can see a tiny spark when you do that, current is flowing to the lights indicating the switch is bad. If you don't see that little spark, you'll have to crawl out and look or have a helper tell you if the lights are on.

If jumping the switch doesn't turn the lights on, we'll have to diagnose a break in the circuit.