I had a perfectly good bulb in the passenger side brake light that didn’t work, I put the bulb on the driver side and it worked just fine. I put LED bulbs in and it work’s on both sides but on the passenger side it’s a little more dim than the driver side. I’m assuming the passenger side isn’t getting enough power because LEDs take less power than a regular bulb. Does anyone know what’s causing this issue or if anyone had had this issue before?

 

I would think more a ground issue rather than power. Multi meter to check if 12 volts/battery voltage to the bulb positive.
Old school incandescent bulb test light to to check for full current for positive and ground---check for power and ground on the socket with the test light. The test light bulb should be full brightness with test light on the power of the socket and the other end grounded. If full brightness then use the test light across the power and ground of the socket to see if the brightness is the same.