LED bulb troubleshooting
7443 / 3157 LED Bulbs — Reverse Color Direction
What to check when parking-light and turn-signal colors or functions are reversed.
View guide →SMD LIGHTING · TECHNICAL SUPPORT
Installation Support & Wiring Guides
Find straightforward installation instructions, wiring diagrams and troubleshooting resources for automotive LED lighting and accessories.
LED Bulbs & Headlight Troubleshooting
Diagnose wiring differences, incorrect lighting functions and common installation problems.
Fuse & socket compatibility
3157 / 7443 RP CK LED Bulbs — SACK / SRCK
Understand reverse-polarity CK sockets and why an incompatible bulb may blow a fuse.
View guide →Headlight wiring
9004 vs. 9007 HID / LED Wiring Conversion
Compare ground, low-beam and high-beam terminal positions before installation.
View wiring chart →Older vehicle conversions
H4 vs. H4666 / H6545 / H4668 Wiring
See how H4 headlight wiring differs from older sealed-beam configurations.
View wiring guide →LED headlight troubleshooting
Using Resistors with LED Headlights & Taillights
Learn when resistors may be used to address certain LED lighting issues.
Read article →Maintenance & performance
Extend the Life of Your LED Headlights
Tips for improving the operating conditions and service life of LED headlight systems.
Read tips →Installation & Wiring Resources
Helpful instructions for installers working with LED strips, switches and vehicle accessories.
LED strip installation
LED Roll Installation
Installation reference for SMD LED rolls and flexible lighting applications.
View instructions (PDF) →Switch diagrams
Rocker Switch Wiring Diagrams
Wiring reference for on/off, momentary, on/off/on and off/on momentary rocker switches.
View diagrams (PDF) →Installer reference
Installer Wire Gauge Calculator
Use our interactive calculator to find a recommended wire gauge based on amps or watts, voltage, and wire length from 3 to 60 feet.
Open wire gauge calculator →