MY TAIL LIGHTS FLASH ON TGHIER OWN IN MY 95 C2500 PICK UP BUT ONLY WITH THE KEY ON IT STOPS WHEN I PUT MY FOOT ON THE BRAKE AND USE THE TURN SIGNALS
Double check and make sure it is the tail lights and not the brake lights, if it is the taillights then it is possible that you have some wiring rubbed through somewhere in the rear wiring that is intermittently touching. If it is the brake lights then the most common is the brake light switch, the return spring inside the switch is getting weak. HTH
Make sure your hazard switch is off all the way. I've seen these switches get stuck, half way pushed in.
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