Wiring with my truck

look for a bad bulb on your truck....I had that happen on a 79 ford pick up I had years ago...I couldn't figure it out...so I took to this garage in town and this old timer came out and looked at it...every light on the truck would blink when you put on the turn signal...he stood and scratched his and started testing all the wires with a test light...it was back feeding....we got to the back of the truck and he removed the bulb on the left side and it stopped everything from blinking....what was wrong was the filament had broke on one side in the bulb (1157) and it dropped down on the on the turn the signal side filament and was back feeding through the truck....we replaced the bulb and all the lights stopped blinking....not sure if this is your problem...but it worked on my truck