1995 Integra RS

I recently had my car down 4-6 weeks and once I've gotten everything back up and running I noticed my o2 gauge flickering...


The o2 gauge is plugged into the dash fuse box and gets its power from the ignition switchs yellow wire. I've disassembled the ignition switch and cleaned it. Didnt help.
I've checked for continuity between main power leg to the yellow wire and it's not receiving power through the ignition switch.. That's when keys off atleast. I tired for continuity between power leg and yellow wire from ignition switch but don't get any. Not sure if this is due to possible resistance or the power source us coming from somewhere else...
From the Integra manual I know this powers mirrors, defroster, heater/fan/ac relays.. Would it be possible for a short on a relay to back feed 5volts?

Any advice would be appreciated.