[Dave at Pelican Parts]

Up through 1973, the 914 tach had separate right and left turn signal indicator lights. For the 1974 model year, that was changed to only one light indicating either turn signal was on. (N.B., some early 1974s used 1973 gauges with the silver center and two indicators in the tach, but they were both wired to blink together!)

That may be the cause of your confusion if your 914 is 1974 or later; there are only wires for the one indicator light.

--DD