The lights of my 2004 206 Peugeot is not working

[raisom]

back light and 1 headlights are not working.I changed the bulb in the back light but it's still not working. The fuses are all good What else could it be?

[brejery]

In my opinion either it could be a wiring problem or an open circuit somewhere.

Get a voltmeter to test the reading at the point of contact to the bulb.

Check if it is rust that is causing the problem.