2006 Ford Ranger. Rear passenger side tail light

You have a short in the cross over wire. Almost all cars and trucks have one main break wire with a second wire "y" in off to the passenger side . You could just wire in a cross over and disconnect the old one.

IS there front park lights? Sounds as if the multi-function switch is defective. The brake lights/park lights to rear run through this switch as well as the signals. ( common problem )

With a test light check if you have power there with lights on and with lights off, compare left side with right side as far as location in the tail lamp plug for the tail lamp park lights.Trace the harness back to the left side underneath usual corrosion in this area.

may have a defective headlight switch or a bad relay for rear lights..

You have a bad connection at the rear passenger side turn signal. It is either the connection is corroded or a wire is loose on the ground side of the circuit.

The characteristic you described is almost always a ground connection that is not secure.

Check with an ohm meter the resistance between the ground at the light socket and the chassis of the car. Any resistance is an indication of a poor ground connection. Temporarily connect the return(ground) connection at the socket to the chassis using a jumper.

If all is correct with jumper in place determine poor connection location and repair.

Hope this helps?

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18

sounds like a ground problem or malfunctioning signal switch

Check correct wattage globe is installed in both front and rear indicator lights;
check if any other side/repeat indicator lights have failed.

Had the exact problem on my 98 ranger 2wd reg cab stepside with the 2.5l 4 banger. Anytime I pressed the brake my passenger side turn signal would light up solid on the dash and the lights outside. I pulled both rear lights and both headlights and turn signals to check for corrosion/loose wires. Nothing. I checked and cleaned all my grounds and fuses. Nothing. Not until I followed my rear taillights wire harness did I find the problem. The two taillights are connected to each other via wire harness. My truck had the harness split with an adapter for trailer brakes. This harness was the problem. It is located under the rear bumper by the spare tire. Simply disconnect two harness plugs going into each side and remove it. Then connect the two plugs to each other. Problem solved.