986 front fog lights
 

My right side front fog light is dim, even after I installed a new bulb

Check the ground connection and contacts in the socket.

Probably a faulty ground. Hard to check, but you can do visual inspection for corrosion and check continuity with a cheap multimeter set to measure ohms. Porsche grounds are generally brown colored wires.

+1 on corroded contacts in the socket. A little contact cleaner and then some dielectric grease could clear it up.

The socket the light plugs into can also come a bit lose in the arm that holds it so the connection isn't made fully when plugged in, mine did and I had odd things like the the fog lights flashing with the indicator... worth a check.

Also, many lights I've looked inside have had cracking and decaying wire coating inside, apparently Porsche used an environmentally friendly coating that breaks down over time.