A/F gauge light shut off

[SpeedNut]

sup guys, i just got 07 wrx and im her 2nd owner. the person before me put some gauges in her and one went out..the air/fuel ratio gauge. but the thing about this gauge is that it has no needle, its a lighting that goes blue to red. it worked the first couple weeks then one day it just stopped working when i was driving. i tapped it, came back on.. then minutes later shut off again and never came back on. the gauges face lights up.. but not the "needle light thingy". so any suggestions of what it could be before i take apart the gauge pod? any help will do. thanks =)

[SuBiEklD]

make sure the electrical plug is in there tight. if that doesn't fix it then you might want to check and see where he spliced the electrical wires and see if they came loose somehow.

[ninefourteener]

It's probably spliced into the O2 sensor... check that connection.