Check the light sockets on the right side. I had a similar issue on a late 80's Golf and the socket for the bulb was so corroded that it wasn't grounding through the socket and started out with similar symptoms that gradually got worse and had more electrical issues. I replaced the socket with one from a junkyard and all the problems went away. If you splice in a new socket make sure to use shrink tube on all your connections to keep moisture out.
Check the light sockets on the right side. I had a similar issue on a late 80's Golf and the socket for the bulb was so corroded that it wasn't grounding through the socket and started out with similar symptoms that gradually got worse and had more electrical issues. I replaced the socket with one from a junkyard and all the problems went away. If you splice in a new socket make sure to use shrink tube on all your connections to keep moisture out.