No power to right side (PS) headlight low beam plug socket, new bulb, fuse is good. High beam works, blinker works, park light works. just no low beam and doesn't register any voltage on volt meter.

I would first check fuses. Make sure you have power to and from the bulb sockets. If not power make sure wiring, grounds and wiring connection are good. Verify you have power to bulb socket, may have bad socket but unlikely all went out at same time. My last thought make sure you have power to and from switches.
Not sure what vehicle you have but these are my thoughts in general.
https://www.youtube.com/watch?v=3zQCG06gFN0
Some vehicles may have a fuse for blinker and even separate fuses for high and low beams. You could have relays for blinker, low beam and third relay for high beam.
If you go to google and put your year make and model also put fuse box diagram or owners manual you may find your fuse box diagram.
example 2015 GMC terrain fuse box diagram
You may have several link pop up if you look through them you may find one which works.
Hope this helps.

If this fuse box diagram below is correct you have a fuse for left low beam head light and another fuse for right low beam head light and a third fuse for both the high beam headlights. If the fuse is good for the right I think I would take the left low beam head light and put on the right side and see if it works on the right side. If you think you got the wiring correct. It may be the bulb is bad from the wires which shorted out. A voltmeter or test light to the socket would save some time switching the lights. I have had the socket bad before and had to change the bulb socket.
https://fusesdiagram.com/ford/fuse-box-diagram-ford-taurus-2000-2007.html

low beam won't light Richard, faulty bulb socket module or wires, check and repair.
Check the attached links,instruction and guides, Good luck
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How to Fix Low Beam Headlight

Low beam headlights out High beam working

High beams ok but not low beam one side only TDIClub Forums

It shouldn't be the high/low beam switch, as that switches the high/low beam relays. One high beam relay supplies power for both sides, one for low beam, both sides. If you were to lose switch function or a relay, you would lose the high beams or the low beams, but not for just one side. It would be interesting to probe the fuses with a test light and see if you're getting power to and through them. If you are, the problem would be between the fuse box and the headlight, if your not getting power to the left head light fuses, the problem will be in the fuse box. Good luck!

seems you have several different problems. High beam working and no low beams=dimmer switch is bad. Reverse lamp not working=bulb socket bad,wiring broke,bad ground at back
Brake light on drivers side stuck on=brake light switch

According to the wiring diagram, there is no relay involved.
The headlight switch provides the ground for the lights and they get power from a fuse for each side. So the high and low beam on one side is powered by the same fuse and the ground is thru the switch.
Could be the switch but chances are a wiring problem.

The problem is a Headlight module. Fuse box under the hood has two black modules side by side, the one on your right is the headlight module the one on the left is the fan module. Try swapping them, if the headlights work replace bad module, don't drive vehicle with the bad module in the fan slot. Mine kept going bad because I had a high intensity bulb on one side.

check the bulbs first and also the fuses theres a fuse for each side and for low and high beams, start there, good luck.

If your getting power at the headlight wire harness, then it's going to be the bulb it self, but make sure your checking the right 12 volt terminal at the plug. There should be three terminals there, there is a ground, 12 volt low beam, and a 12 volt high beam. If both the low and high 12 volts are getting power, then it's going to be the head light bulb it self that has reached the end of it's life time since the day time running lights are always on which is the high beams. Good luck and check the fuse box under the hood by the battery. 

Power flows from the battery to the main fuse. Then it flows to the control coil and contact side of the headlight relay. When you turn on the headlights, the headlight switch provides ground to the control coil in the headlight relay and that operates the contacts. The contacts allow power to flow to the right and left hand headlight fuses. Power flows to the headlights. The headlight switch is what provides ground to the high and low beams on the headlights.

To diagnose, remove the headlight relay. Using a voltmeter, check for battery voltage on terminals 3 & 4 in the socket with the key in the RUN position. Then turn on the low beams. Test for good ground on terminal 1 in the socket. If you're not getting ground, then you've got a problem with either a bad headlight combo switch or a bad ground. If you get good ground on terminal 1, reinstall the relay, turn on the low beams and test for power in the headlight sockets. If you get battery voltage, that confirms you've got good fuses and wiring up to that point. Next, check for good low beam ground on the red/green wire in the bulb socket. If you're not getting good ground, it's either a bad combo switch or bad ground from the combo switch. Then turn on the high beams and check for good ground on the red/yellow wire in the bulb sockets.

It wouldn't hurt to clean the ID ground on the left side of the instrument panel, but based on everything you've said so far, this sounds like a bad combo switch