My horn just quit working in overhead. anyone know for sure where ground goes to. I was just working under pilot side inst access replacing PC gyro and removed the PC turn coordinater power supply. maybe i missed or disturbed the ground. Figures been working off all my sqwaks and just as i finish something else comes up. I have in last two months OH complete INJ system servo spider ,all new landing gear biscuits to include new NLg truss stc rewired my dash backlighting which was inop. fixed PC vacume leaks and OH the pc gyro, and replaced CHT probe .By the way Brittain is awsome to work with and fast. My turn coordinater gyro was original 1969 never overhauled and gimble was still good. 450 ish to re build. works like a champ now