A short, or something else?

I have what I believe to be a weird issue, and need some help trouble shooting.

My instrument cluster lights work IF I twist the dimmer to just the right spot.
They do go on and off if it's not set just right. Could that be a short somewhere?

My LEFT turn signals work (both on the top fender and cluster), but the RIGHT side does not.
However, when I turn on the blinker I can hear it working, it's just that the fender indicator and cluster indicator lights don't come on. They were working yesterday!

Where would I begin to look for and repair the culprit?

This is on a '74 Plymouth Scamp / 318, w/ AC.