my reverse lights don’t come on when engaged.
The problem might be with the park/neutral safety/range switch.
This switch not only prevents the starter from operating unless the transmission is in park/neutral, and tells the computer what gear is selected, it also turns on the reverse lights when the transmission is shifted into reverse.
Check the resistance in one of the bulb’s filaments before considering the switch mentioned above. If it measures less than 10 ohms the bulb is ok, and as long as you see no signs of corrosion on the bulb connector/socket, that would point to the switch (or less likely, a bad ground at the tail lights) being the problem. That switch on my truck hasn’t worked in years … lol …