you got to replace to light bulbs
you could have possibly bought the wrong bulbs and/or fuses. or when you were replacing them you may have damaged the wires. Also the reverse light switch may be defective.
Could be a linkage problem..
Take it out of reverse.
what to do if my reverse lights on my 1993 gmc 1500 truck wont work
Most likely the reverse lights were attached to the light bar.
open the doors and look for two little phillips head screw heads that are actually set back into holes in the metal. use a magnetic screw driver so the screws wont fall inside the fenders the pull the light out and to the side. you can then unscrew the cover over the light bulbs to access them. reverse procedure to reinstall.
well then it seems like you have a problem!
Remove the control head and examine the electrical connections in back. You may find a connection that has melted from to much resistance(dirty/loose).
Bulb is blown or has been removed.
it is obviously broken. you'll need a new light fixture
depending on the year you can disconnect the positive battery cable for a few minutes and then reconnect it. it may reset the security system.
What you do is get a new charger.that's what is what was wrong with mine