If the farthest light has two wires coming in, then that is not the last light in the circuit, or its on a 3 way switch. It’s possible that the working bulb is actually the first bulb in the circuit abd that the circuit is broken between it and the next bulb. Look for a loose or chewn threw wire at the working fixture, and the next closest one. Make sure to turn off the breaker before touching anything inside the fixtures. I might also recommend an inexpensive voltage tester like this one https://www.homedepot.com/p/Klein-Tools-Non-Contact-Voltage-Tester-NCVT-1SEN/100661787?cm_mmc=Shopping%7CTHD%7CG%7C0%7CG-VF-PLA-D27E-Electrical%7C&gclid=Cj0KCQiA-ebSBRC8ARIsAGuxJIpGoJxumrrGr1FKpxXhno-H60NiYhFn7G7TfVZ-N3TNr2v4rLuZ7b4aAkN3EALw_wcB&gclsrc=aw.ds&dclid=CO2lms_41dgCFUeoaQodDkAAiw. With the fixtures pulled away from the box, but still wired, turn the power on and check to see if voltage is present at the fixtures.

if you’re not comfortable with any of this, it might be best to hire an electrician.

Got it. So if that fixture is the first, and the circuit is broken between it and the second light, that first fixture can still work? Either that, or they are somehow wired in parallel?

What if the wire is damaged somewhere that is unexposed, like behind the brick wall? The area behind the brick wall is full of dirt. At that farthest working fixture, it’s down about 6 feet from the surface of the dirt behind the brick wall. I’m doubting that they use some sort of conduit to run the wire (built in ‘89), so I’m guessing that wire is not going to slide in or out of there easily, is it?

Yes. There will be a connection between the power coming in, the connection to the fixture itself, and the feed to the next fixture in the circuit. A bad connection can cause either the light there to not work or the ones further down to not work (either or both).

It's not too likely, but you might get lucky and find that removing the wire nuts, cleaning the copper wires with a bit of sandpaper, and installing new wire nuts fixes it. You might even find a wire that got nicked during installation and broke at that connection.

But if you do have a break in the buried wire, most likely there's some shovel work in your future, or your electrician's.

The buried cable is most likely not conduit, but rather UF (underground feeder), a flexible cable designed for direct burial. At least let's hope it is, and not something that's failed because it wasn't suitable for burial.

Here's yet another anecdote (I'm just full of them). The PO of my current house ran power to an outbuilding with NM (bad idea). He started to bury it (NM isn't designed to be buried), and eventually decided that digging was too hard and just left the rest of it lying on the ground (NM isn't meant to be exposed or in wet areas).

I have no idea how many years it had been like that, but here's what it looked like when I pulled it out.

If the wire between the working and non-working fixtures is damaged, you have 3 options. Fix it, replace it, or deal with non-woking lights. Start with the easy stuff first. Chech your connections, and use a voltage tester or multimeter to determine where voltage is and isnt to find your problem.

It is possible they are in parralel, but there would be no reason for wires to go back out of the box, so unlikely.

Steve, sorry, I don't understand what you mean. Maybe you're using a different definition of the word "parallel" that I don't know. I hope you can explain it to me.

As I understand basic electricity from my early childhood tinkering with good old #6 dry cells, all the lights here are definitely connected in a parallel circuit. They're sure not in series!Note that each line in the image below represents a single conductor, not a cable, and the grounding conductor is not shown.

If the problem is indeed in buried cable, yes, you can fix it if you can find exactly where the damage is. That's why the ancient Greek gods gave us mortals tone rangers and underground splicing kits. :)

Here it sounds like the lights are pretty close together. By the time you get done buying or renting a tracer, it's going to be just as easy to dig a little more and replace the entire run that has the fault.

BUT: check all the connections and test with an ohmmeter or continuity tester before you drag out the shovel. If you're lucky, it might be right there in one of the boxes.

Thanks everyone. I just ordered the quick voltage tester that Steve suggested to be safe (vs. using my multimeter). I'll check the connections in the boxes first and hope for the best.

I do not like the idea of having to dig. My house is set into a hill, so the first floor is actually one floor up from the driveway (never buy a house with a hilly yard. :-/). A set of stairs takes you up to the front door. The bricks are part of a wall along the stairs that holds in a 1 story tall planter full of large plants. I'd have to dig a bung of plants out and stand in a kinda cramp space in order to dig out the dirt. Not even sure where I would put the dirt. :(

Viche, FYI the tester is not inherently safer except that it works better saving frustration and frustrated workers can get dangerous. An electronic voltmeter has too little impedance to work well in some instances. Sometimes you can get currents with considerable voltage induced in conductors. They can drive you nuts with their indications of voltages that vary all over the place. A yes/no detector that provides a load will fix that, faster, and better.

" ...never buy a house with a hilly yard. :-/" makes me smile recalling my time in Pittsburgh. If a real estate ad was going to have it. "level yard", it was in the first line of the ad.

It appears that if you want lights there and don't want to dig behind the wall, some low voltage replacements might be in your future. Find where the circuit goes underground. That is where you install your power supply for the LED lamps if it is not too far away. Running low voltage is less demanding. If the junction box is too far away (voltage drop), you can bury underground cable to a closer point.

LOL @ DavidR's anecdote. It is not every day that you find that someone can break two rules with only one cable between splices, but I bet others will post.

Ionized, I thought the voltage tester was safer because the tip is insulated and can't cause a short circuit. Also, I thought a multi meter could fry if you didn't use the right setting or the right wire holes, and then you had to make sure you touched the ground before the active wire. The tester seems more foolproof, or at least fool-proof.

Re: low voltage lights: even if I switch to those, I'd have to dig down 6 feet to get the wire to the box wouldn't I?

Yes, there are other advantages to the touch testers. I like my "wiggie" solenoid tester. It is a good investment if you are gong to do a lot of this.

If you go low voltage you can run the wires on the surface and use or hide the boxes (as long as they are disconnected) as you like. Although it is a good idea to bury the cable deep enough so it won't be damaged, you can really do what ever you want with it.

By boxes, I meant the boxes that house the light fixture. Even if I run a low voltage wire on the surface, I still need them to reach the light fixtures that are up to 6 feet below ground. For illustrative purposes, see below.

Now imagine the wall is twice as high and running along a set of stairs, with the light fixtures a couple feet from the ground. I would need to balance near the top edge of the wall as I out the plants, and throw the dirt down onto the stairs?

Yes, you are correct. If the wires are in fact bad, there will be nothing easy or clean about it. Somebody will need to get dirty.

DavidR, you are in fact 100% correct, I was in fact meaning parralel. Not sure why I noted series.

Let's hope you don't have to replace one or more buried cables! But if you do, here's what I might try instead of digging. I haven't actually tried this, so others here are welcome to say it won't work if they think it won't.

It'd be time consuming, but IMO easier. I'd get out my impact drill, put a chisel bit in it, and chisel out the mortar between about every other brick in the wall, maybe even every third brick. I wouldn't remove every brick, something has to hold the wall up!

Then I'd reach back in behind the remaining bricks with a trowel or whatever, and dig out the dirt straight across. Fish the new UF cable (now trivial), pack the dirt back in, slap some fresh mortar down, shove the bricks back in, and tuckpoint the sides and top of each removed brick. Done.

Another thought. I wonder if you can put enough extensions on a one-person posthole digger to get down 6 feet. You only need to bury the UF 12" deep if it's protected by a GFI, though I prefer around 18" as 12" seems awfully close to shovel depth.

Trench that depth, and the use the posthole digger to get down to the light level. Potential problem: damaging the existing feeder cable, presumably still OK, with the auger.