Holley's RetroBright LED headlights are available in three color temperatures (5700K, 3000K, and European-inspired Yellow). Each light includes instructions, an adapter harness, and terminals to cover just about every wiring situation.

To convert this 1986 Mustang to Holley's RetroBright LED headlights, we chose four 4" x 6" 3000K lights (p/n LFRB120).

We started the installation process by removing this Saleen Mustang's headlight covers.

Then, we removed the four screws and the headlight bezels.

With the bezel removed, we unplugged the factory harness from the high beam bulb.

Next, we removed the low beam bulb.

The OEM harness and plug were in good condition, but the terminal positions differed from the Holley RetroBright plug.

The high beam plug only had two terminals.

We had a wiring diagram for our Mustang, but we used a multimeter to verify the positions and polarity of the high and low beam wires...just in case.

There are two ways to wire up the Holley RetroBright LED headlights. One method uses the included adapter harness.

Using the included instructions, we assembled the adapter harness with the terminals in the correct positions to match our Mustang's OEM harness.

Another option is to disassemble and re-pin the factory connector to match the Holley RetroBright plug. While this solution uses less wiring, be mindful that the factory wiring will be altered, and it won't work with a standard replacement halogen bulb any more.

We chose to re-pin the factory harness so the Holley RetroBright harness plugged right in.

The Holley RetroBright housing fit the factory bucket and bezel just like the standard headlight.

For the high beam, we also had two wiring choices. If we removed the low beam terminal from the Holley RetroBright headlight, it plugs directly to the factory harness.

The other option is to use the included adapter harness but remove the low beam terminal per the instructions.

We used a small flat blade screwdriver to remove the blue (low beam) wire from the adapter harness.

We chose to use the adapter harness on the high beam side rather than permanently alter the Holley RetroBright plug to fit the OEM connector.

We installed the Holley RetroBright bulb using the factory bezel and hardware.

Compared to the factory-style halogen bulb (left) the Holley RetroBright lights are brighter and the beam spread pattern is wider. Nice!

1979-1986 Mustangs have a "graphic warning module" that alerts drivers of malfunctioning lights. It compares voltage in each light circuit to the supply voltage. If the voltage differential is too low, it assumes a light is burned out. Since our Holley RetroBright headlights drew less current than the factory bulbs, the voltage in the headlight circuit was high enough to trigger the warning light.

Rather than deal with a false warning light, we located and removed the headlight circuit voltage sensing wire from the connector behind the graphic warning module. (On this 1986 Mustang, it was the brown wire with a blue stripe.)

We taped off the loose wire and labeled it for future reference.

Even when off, the Holley RetroBright LED headlights gave this mustang a clean, crisp appearance that's similar to OEM…but better.

The Holley RetroBright LEDs are significantly brighter than the OEM halogen bulbs, but draw less current—perfect for this Mustang's vintage electrical system. We also found the high beams flash on and off more quickly for better flash-to-pass performance. That's a win-win!