May be a bad signal bulb as in filaments crossed internally, socket problem (grounding, cross connect) Does all the cluster seem to operate OK, lamps, gauges, etc?
Pull the front bulb on that side and see if the problem with the indicator goes away
I will try puling the bulb. The temp gauge has an issue that I haven't dug into yet. I'm thinking it pegs to the right. I will have to look again. The rest of the cluster seems fine