either the switch is not working or a wire to the switch is broken
check your wiring for your lights under the dash or a bad ground
Check all you fuses that is a good possibility that's what wrong.
Check the panel lights resistor switch and be sure that they are not turned off.
Bad bulbs ?- they are double filamented with the larger being for the tailights Bad switch?
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.
there broke there broke
If all the fuses and bulbs are new and work properly, the lights could be malfunctioning due to a short in the wiring. The wiring may also be damaged or burned out in places.
Check wiring harnesses - prone to corrosion
It is either a bad relay , cut wire or the wrong wattage bulb .
Check to see that the wiring is still in good shape and that they are all connected. As my previous car aged, this was a problem. Also, check the bulbs and their sockets. Sometimes they are dirty or no longer seat probably.