How to find shorting ground on a car?

“I saw your video on short circuits on UTube but I need more help. I know I have a “short” in my left park/side marker/tail light circuit as it is blowing the fuse. How do I find where the short is located so that I can fix it? My multimeter indicates power to ground continuity at both ends of the car, even with the fuse out. I am concluding that means the power wire must be in contact with the frame somewhere – but where?!”

That is correct, but finding where the short exists is ALWAYS the hard part. Concentrate your efforts FIRST at each end of the circuit–the switches that operated that circuits (like headlight switch), and the end of the circuit (the circuit board and sockets that contain the light bulbs.) Normally a problem will exist at one end or the other. If the problem is the wiring inbetween, then look for body damage, or things that move (like power seats) which the wires travel through. Normally, the problem lies in the circuit board and sockets where the wires end in most cars. Good Luck,