From an earlier thread...

You will probably find that the lights are still too dim with the rheostat to full right. I've found three things that help to get adequate illumination: 1) clean and polish the inside of the lens with plastic cleaner and polish (Novus), 2) replace the bulbs with new, and 3) bypass the rheostat by soldering a jumper across the terminals.

Barrie
'86 300E
-------------------------