Since my tach didn't illuminate I saw a small hole in the back of the tach and I assumed it was for a light bulb, The actuall light for the tach at the end of a long peddasill was in fact burnt out. I have an after market radio and an extra light with a grey and pink wire on it, maybe that wires for the radio ,I don't know. Anyway all my instrument lights work now and if anybody has an idea where my extra light goes please let me know. It has a black plastic insert by the bulb and all the rest on my cluster are white plastic round ones.Thanks.P.S.What's the small hole in back of the tach. for?