kamikazek9

The fuses were checked. I changed the reverse switch on the transmission, and I figured that either the wire is broken or a bad ground.

A-series

This is gonna sound stupid but, just to make sure, you have the ignition turned on when you look for reverse lights, right?

I assume it's a manual, correct? (said switch and not range sensor or whatever it'd be)

Also, you didn't mention checking the bulbs but I'll assume you did that too.

You could try bypassing that switch, jumping the connector to see if that works but if you're sure the switch is good that pry won't help.

If it's both lights being affected and not the switch I'd check to make sure all connections (start with those easiest to access) are clean and tight.
I know some people have had your problem and it was because a connector somewhere down the line had worked it's way loose.

kamikazek9

Changed the bulbs. I guess I need to actually trace the wires through the car and see if they are damaged or to check the grounds