If you’ve ever walked outside at night and noticed half your landscape lighting working, a few fixtures flickering, and others completely out—you know how frustrating outdoor lighting problems can be.
And if you’ve already tried to fix it—replacing bulbs, tightening connections, maybe even swapping a fixture or two—only to see the problem come back after the next rain… you’re definitely not alone.
Across the DMV, this is one of the most common calls we get:
“Parts of my lighting system keep failing, and I can’t figure out why.”
After more than 42 years serving homeowners throughout Maryland, DC, and Northern Virginia—since 1983—designing, installing, and repairing outdoor lighting systems (and earning over 600 reviews averaging 4.8 stars with an A+ Better Business Bureau rating), I can tell you this:
👉 Multiple lighting failures are almost never separate problems. 👉 They’re symptoms of a system issue.
This case study walks you through how we diagnosed and repaired a lighting system with multiple failures—and why the fixes worked long-term.
The Initial Call: “Some Lights Work… Some Don’t”
This homeowner in Fairfax County reached out after dealing with intermittent lighting issues for over a year.
Their description was typical:
- “The front lights work most of the time” • “The side yard lights flicker or go out after rain” • “The backyard lights stopped working completely”
They had already tried:
- Replacing bulbs • Resetting the transformer • Tightening visible connections
Each fix helped briefly—but the system never stayed consistent.
👉 That’s always a clue that the problem isn’t at the fixture level.
What We Saw on Arrival
Before touching anything, we did a visual walkthrough at dusk.
Here’s what stood out immediately:
- Inconsistent brightness between fixtures on the same run • Two fixtures that were completely out • One zone that dimmed significantly after 10–15 minutes • Several fixtures sitting in areas where water pooled after rain
None of this looked catastrophic on its own.
But together, it pointed to one thing:
👉 System integrity was compromised.
The Big Idea: Lighting Systems Are Only as Strong as Their Weakest Link
Outdoor lighting systems—especially low-voltage systems—depend on three fundamentals:
- Consistent voltage delivery • Protected, sealed connections • Durable fixtures designed for outdoor conditions
If any one of those breaks down, performance suffers.
If multiple break down at once:
👉 You get exactly what this homeowner was experiencing
The Diagnosis Process (Step-by-Step)
We don’t guess with lighting issues—we test.
Here’s how we approached it.
Step 1: Verify Transformer Output
We checked the transformer first.
- Output voltage was within expected range • No immediate signs of failure
This told us the problem wasn’t at the source.
Step 2: Test Voltage Along the Line
Next, we tested voltage at different points along the lighting runs.
Findings:
- Strong voltage near the transformer • Noticeable drop further down the line • Significant drop at the far end (where lights were out)
👉 This indicated voltage loss—usually caused by resistance or poor connections.
Step 3: Inspect Connections
This is where things became clear.
We found:
- Standard wire nuts used instead of waterproof connectors • Several connections exposed to soil moisture • Signs of corrosion inside multiple junctions
This is one of the most common failure points we see.
👉 Water + electricity + poor connections = failure over time
Step 4: Check for Water Intrusion in Fixtures
We opened several fixtures.
Findings:
- Moisture inside two fixtures • One fixture with visible corrosion at the socket • Another with a compromised seal
Step 5: Evaluate System Layout and Load
We also looked at the overall system design.
We found:
- Multiple fixtures added over time without recalculating load • Longer runs than originally designed • Uneven distribution of fixtures across zones
👉 This contributed to voltage drop and inconsistent performance
The Root Causes (Why the System Failed)
At the end of the diagnosis, we identified four main issues:
- Water intrusion at connections
- Corrosion from long-term exposure
- Voltage drop due to extended runs and added fixtures
- Aging fixtures with compromised seals
None of these alone would necessarily take down the system.
Together:
👉 They created cascading failure
Why the Homeowner’s Fixes Didn’t Work
This is important.
The homeowner replaced bulbs—and saw temporary improvement.
Why?
Because bulbs were not the root issue.
The real problems were:
- Electrical (voltage and resistance) • Environmental (moisture and corrosion) • Design-related (load and layout)
👉 Fixing bulbs is like changing a tire when the alignment is off
The Repair Strategy (What We Actually Did)
We didn’t replace everything.
But we also didn’t just patch the obvious issues.
We corrected the system.
Step 1: Replace All Compromised Connections
We removed all non-waterproof connectors and replaced them with gel-filled, weatherproof connectors.
Result:
- Eliminated moisture intrusion at critical points
Step 2: Repair and Replace Damaged Fixtures
We:
- Replaced fixtures with failed seals • Cleaned and restored salvageable units
Step 3: Rebalance the System Load
We redistributed fixtures across runs to reduce voltage drop.
In some areas, we:
- Shortened runs • Split zones for better performance
Step 4: Adjust Transformer Settings
We optimized transformer output for the revised layout.
Step 5: Improve Drainage Around Fixtures
In areas where water pooled, we:
- Raised fixture bases slightly • Improved surrounding drainage
👉 This prevented future water intrusion
What Happened After the Repair
Immediately after repairs:
- All fixtures illuminated evenly • No flickering • No dimming over time
The Real Test: After Rain
This is where most systems fail.
After the next heavy rain:
- No outages • No flickering • No dimming
👉 The system held steady
Long-Term Results
Over the following year:
- No repeat failures • No maintenance calls • Consistent lighting performance
Homeowner feedback:
“We thought we’d have to replace everything. This finally works.”
Cost Breakdown
Previous DIY + repairs: • ~$500–$800 spent over time
Professional repair and correction: • ~$1,800
Full replacement (if needed): • $3,500–$7,000+
👉 Repairing correctly saved thousands
What This Case Study Teaches
- Multiple Failures Usually Share a Root Cause Fixing each light individually won’t solve a system problem.
- Water Is the #1 Enemy of Outdoor Lighting If connections aren’t sealed, failure is only a matter of time.
- Voltage Matters More Than Most People Realize Distance, load, and wiring all affect performance.
- DIY Fixes Often Address Symptoms Without diagnosing the system, problems return.
- You Don’t Always Need a Full Replacement But you do need a full understanding of the system.
How to Know If This Applies to You
You may be dealing with the same issue if:
- Lights fail after rain • Some areas are dimmer than others • Fixtures flicker or cut out • You’ve replaced bulbs but problems persist
What Happens If You Ignore It
If these issues are left alone:
- Failures increase • More fixtures stop working • System efficiency drops • Costs rise over time
Homeowner Decision Guide
If you’re dealing with multiple failures:
- Don’t start with bulbs • Don’t assume it’s one bad fixture
👉 Start by evaluating the system as a whole
Schema / Quick Answers
Q: Why do outdoor lights fail after rain? A: Water intrusion at connections or fixtures.
Q: Can I fix this myself? A: Temporary fixes are possible—but root issues often require full evaluation.
Q: Do I need to replace the entire system? A: Not always—many systems can be repaired if diagnosed correctly.
Final Thoughts
If your outdoor lighting system has multiple failures, it’s not random.
It’s a pattern.
And once you understand the system behind that pattern, the solution becomes clear.
After more than four decades helping homeowners throughout the DMV, I can tell you this:
The best lighting systems aren’t the ones that never need attention.
👉 They’re the ones designed and repaired to handle real-world conditions.
And when you fix the system—not just the symptoms—you finally get consistent, reliable performance.