Take the gauge cluster out and see if the pin is messed up, the wire is loose in the plug, or if the board is messed up.

I have a right turn signal that doesn't turn on in the dash either.

Turns out part of the board peeled. Delaminated, or whatever they call it and the circuit to that light is bad. Scraped it away and ran a bead of solider to connect the points and it worked for a while.

Just waiting now for the guy making new boards to finish the one for my car so I can replace it instead of the rigged thing that doesn't work anymore.