I drive a pickup. The reverse lights are with the tail lights or on some with custom lights they might be in the bumper. The lights on the back of the cab are load lights. They are intended to give light so you can see what you are loading, unloading or check that your load is secure. There is a switch on the dash that you turn on and off. If you do not check the switch to make sure they are off, you may not realize they are on due to the light outside and it being dark inside the cab.
If any ladies would like to check my load for me let me know. I will be in Austin 18-22 Nov.