Brake light will work but not running light in rear drivers side

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.

Please clarify you statement .

Start by replacing the light bulb.

The brake light side of the bulbs is powered by the brake switch and travels thru the turn signal switch.
If the third brake light works, I would guess the problem is in the turn signal switch.

Since the high mounted brake light works you know that the brake light switch is working. Now you need to check the brake light bulbs in the rear tail light assemblies. The brake lights are separate from the tail light (parking or running lights). There are two screws that hold the rear light assemblies in place.

will u have a few more switches and relays to check/change brake light switch and relay/and headlight switch

I had the same problem. They were on when the headlights were on, but turned off instead of brightening when I pressed the brake. I replaced the bulb and now it gets bright when I press the brake instead of turning off (like it should).

If the driver's side tail light is working, it's not a fuse. Use a test light to check for power at the bulb holder. One terminal will be for tail light, the other for brake/turn light. If the is constant power for tail light, replace bulb. If no power, trace wiring from bulb holder to driver's side junction. Probable broken wire between the two tail lights.

Test the connectors that the lights go in with someone applying the brake. These connectors are not very well made. You may need a new connector on the side that's not working.

check the wire harness that runs from inside the trunk on the drivers side follow it down to the tail light and make shure the wires are not damaged or unplugged remove cover on the drivers side inspect the bulbs the holders and the wires and dont forgt to retighten all grounds that you find on your travels this should get the rear tail lights working also check the brake pedal switch up on the metal part of the brake pedal arm follow it up tp the brake pedal switch and acuate the switch by hand and check the wire voltage coming in and going out when pressing the brake pedal ok give this a shot