Component Description

WARNING: This page is about a different car, the 2015 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.

Headlamp Assembly

Vehicles with LED headlamps utilize a ballast, mounted to each headlamp assembly, that controls the voltage to the high beam, low beam, parking and turn Light Emitting Diodes (LEDs) within the headlamp assembly and the low beam DRL function.

Exterior lamps are vented to accommodate normal changes in pressure. Condensation can be a natural by-product of this design. When moist air enters the lamp assembly through the vents, there is a possibility that condensation can occur if the temperature is cold. When normal condensation occurs, a thin mist forms on the interior of the lens. The thin mist eventually clears and exits through the vents during normal operation. The amount of time it takes to clear the lens of acceptable mist varies with ambient humidity and lamp types. Normal condensation clears from any lamp in 48 hours under dry conditions.

Do not replace a lamp assembly with acceptable levels of condensation such as:

presence of thin mist (no streaks, drip marks or droplets are present)
fine mist covers less than 50% of the lens

Examples of unacceptable moisture (usually caused by a lamp housing leak):

water puddling inside the lamp
large water droplets, drip marks or streaks present on the interior of the lens

Headlamp Switch

The BCM monitors the headlamp switch position by sending voltage signals on multiple circuits to the headlamp switch. There is one circuit for each headlamp switch position. At any given time, one of the signal circuits is switched to ground to indicate the headlamp switch position.

Ballast

A ballast is mounted to each LED headlamp assembly. The ballasts control the voltage to the high beam, low beam, parking and turn Light Emitting Diodes (LEDs) within the headlamp assembly and the low beam DRL function.

Light Sensor

The BCM sends a voltage signal to the light sensor. The light sensor provides resistance between the voltage signal and ground. The resistance varies depending on the amount of ambient light detected by the light sensor. The brighter the ambient light, the lower the resistance. By varying the resistance, the BCM can determine the amount of ambient light.

Stoplamp Switch

The stoplamp switch is a normally open switch and is provided voltage at all times. When the brake pedal is applied, the switch closes and routes voltage to the BCM.

TRM

The TRM recieves inputs from the BCM to control voltage to the trailer tow connector for the LH stop/turn, RH stop/turn lamps and trailer battery charging.