I am new here and recently purchased a mostly original 1969 SS 396 Auto car. I had a retro sound radio put in this week. Everything was fine before this. Now the left turn signal is always on even when the ignition is off. it constantly flashes on the dash and at the lamp. The right signal indicator does not work now. All the lights work properly when the car is running. the left signal just will not stop. Is this a possible ground issue? Is this a turn signal switch issue, or is this improper wiring on the radio install wiring? Any help would be appreciated.