By far, one of the worst things that can happen when you’re working with stage lighting is this: your lights just don’t work right.

Maybe they’re not doing what you told them to do. Maybe they’re showing the wrong color, or worse—not responding at all. So, how do you fix it? Where do you start? And what’s the most reliable way to get them working again?

 Demo Setup

In the video demonstration here, I’m using a simple rig:

• ColorKey Mover Spot 150
• ColorKey Mover Wash HEX 12
• ADJ WMX1 MK 2 

This is a small setup, but it’s perfect for showing the types of problems you might encounter—and how to fix them.

Step 1: Check the DMX Address and Mode

One of the most common causes of DMX issues is a mismatch between your console’s patch settings and your fixture’s actual configuration.

Start by checking two things in your console's patch or your notes/records:

1. DMX address – Does the fixture’s address match what’s in your console patch?
2. DMX mode – Is the fixture set to the right mode (number of channels, profile type, etc.)?

In the video, I deliberately changed the fixture’s DMX channel from 16 to 14. As you can guess, the light stopped responding the way it should. Once I put it back to 16, some things worked—but the colors were still not changing. That’s because the mode was wrong too.

When the address is correct but the mode is wrong, the light will often respond in weird ways. Fix both, and you’ll solve about 90% of DMX problems right there.

Step 2: Compare with a Known Good Fixture

If the address and mode are correct but the fixture still isn’t behaving, here’s my next move:

• Put the misbehaving fixture on the same DMX address and mode as a fixture that’s working correctly and is nearby on the same universe.

If both are set the same and only one responds correctly, you might have a fixture problem—but it could also be a wiring or termination issue. This step helps you narrow it down.

Step 3: Check Your DMX Universes

A surprisingly common issue? Lights plugged into the wrong DMX universe.

Fixtures don’t know about “universes” the way your console does—they only know channel numbers and modes. If they’re patched in universe 1 but physically plugged into universe 2, you’ll get unpredictable results.

How to Verify:

• Check your console output settings.
• Verify your DMX node or splitter configuration.
• Make sure the correct universe is going to the correct cable run.

Step 4: Look for Wiring Problems

If you’ve ruled out address, mode, and universe issues, the problem might be in your cabling or termination.

Here’s what to watch for:

• Sound-active or auto modes – Sometimes a fixture in auto or sound-active mode will actually send DMX out to others in the chain, messing everything up. (Note: If you’re using DMX splitters, signals won’t cross splitter ports.)
• Improper cables – Microphone cable can pass DMX, but it often causes problems. Use proper DMX cable. (I recently did a video on the difference between DMX and Microphone cables and why it matters - check it out here!)
• Termination issues – Long runs or bad cables may require a DMX terminator to stabilize the signal.

A quick test:

• Disconnect the full DMX chain from your console.
• Run a single, known-good DMX cable directly from the console to the problem fixture.
• If it works fine now, the issue is somewhere in your wiring—not the fixture or console.

Sometimes, inserting a DMX splitter mid-run can also help solve termination-related problems.

The ENTTEC D-Split is a 4-port DMX splitter

Wrapping It Up

These steps cover the most common DMX lighting issues I see:

1. Check address and mode – the root of most problems.
2. Compare with a working fixture to rule out fixture failure.
3. Verify universes – they must match.
4. Inspect wiring and termination – the “hidden” troublemakers.

If you’re new to DMX lighting, I’ve put together a free guide at Learn Stage Lighting that walks you through getting started with your specific type of setup.

And if you’re in the market for lights—like the ColorKey units in this demo—or anything else lighting/audio/video-related, check out Above AVL. We stock thousands of items, offer personalized quotes, and would love to help you get the perfect gear for your events.

Here’s to keeping your lights happy and your shows running smoothly!