Electricity

12V DC Landscape Lights Jamming Garage Door Opener (Random Opening)

HainKurt 30/06/2026 - 8:02 AM

Hi Pros, I have a strange issue and cannot find a solution, and hoping someone out there can help me... I installed a 12V DC landscape lighting system (10 LED fixtures). Power is supplied by a 60W DEWENWILS transformer (and I also tested a 100W unit from another brand). When the lights are ON, my garage door remote range drops from 300+ ft to ~50 ft, and worse, the door randomly opens on its own at night. Troubleshooting performed: Tested with lights OFF → remote range returns to 300+ ft ✅ Tested with 2 LEDs only → range ~250 ft, no random openings ✅ Tested with 4 LEDs → range drops to ~50 ft, random openings occur ❌ Installed ferrite cores on 12V output & each branch → no improvement Extended the opener's antenna with coax (center conductor exposed, shield grounded) → range improved slightly, but random openings persist Swapped transformer (60W DEWENWILS → 100W other brand) → no improvement What I know: The problem scales with the number of LEDs (more lights = worse interference) The issue is radiated EMI from the LED fixtures themselves (not conducted through the power lines) The random opening suggests the EMI is strong enough to mimic the opener's rolling code signal Goal: I need to stop the random openings without replacing the entire lighting system or switching to MyQ/Wi-Fi. Are there specific types of 12V DC LED bulbs known for low EMI or FCC Part 15 compliance? Would shielding individual fixtures with copper tape/foil (grounded) be a viable path? Open to other ideas. Setup: Opener: LiftMaster/Chamberlain (rolling code, 315/390 MHz) Transformer: 60W 12V DC (DEWENWILS) / 100W DC (other brand) LED fixtures: Standard 12V landscape spotlights (integrated driver, 12V DC compatible) Location: Lights are mounted on exterior walls and soffits, surrounding the garage on 3 sides... Thanks for your time/interest...

GTA Handy Pros

Rating: 5 out of 5

5/51 review

Toronto

The issue is caused by high-frequency harmonic noise generated by the internal drivers of your landscape LEDs. This noise mimics rolling codes and blinds your LiftMaster receiver. To fix this permanently without switching to Wi-Fi, you should replace the current LED bulbs with premium FCC Part 15 Class B certified low-EMI bulbs, or solder \(0.1\ \mu\text{F}\) ceramic capacitors across the 12V power lines at the fixtures to short-circuit the radio frequencies before they can radiate.

Answered30 June 2026

Like

0

---