• 2021

Let There Be Light

Headlamp Basics and Service Procedures for Select FCA US Vehicles

Headlamp Basics

Headlamps have changed considerably over the years. Sealed beam headlights have gone away and today’s headlamp bulbs are brighter and whiter than their predecessors. It’s easy to spot an older car at night because the headlamp bulbs have a yellowish cast to their light, whereas newer cars have a whiter, cleaner light. The same can be said of fog lights. In years past, fog lights were not factory-installed items. If a vehicle had fog lights, they were aftermarket add-on items. These days, however, many more vehicles have some kind of fog lighting system than those that don’t.

Figure 1 shows the position of the headlamps and fog lamps on a 2015 Chrysler Town & Country.

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Figure 1

Not all headlamps are created equal. The Dodge headlamp system utilizes a quad halogen headlamp that includes two single filament halogen bulbs in each front lamp unit (one bulb is low beam, the other bulb is high beam). This quad system is standard on the Chrysler Town & Country. The optional headlamp system features an HID (High Intensity Discharge) lighting element/igniter unit for the low beam headlamps and a single filament halogen bulb for high beam.

The HID lamps require an electronic ballast module. This is how that lamp works. The HID electronic ballast module uses a high voltage Alternating Current (AC) output to activate the HID igniter integral to the lighting element to provide a high voltage surge, which creates a light arc between the lighting element electrodes. Once the electronic ballast module detects a suitably stable light arc, it switches over to a power-limiting mode to sustain the light arc.

The Chrysler 300 / Dodge Challenger / Jeep® Grand Cherokee have two headlamp systems available. The standard halogen headlamp system includes a bi-functional single filament halogen bulb in each front lamp unit for low or high beam headlamps. The optional HID headlamp system includes a bi-functional single HID lighting element/igniter unit for low or high beam headlamps.

Headlamp Service

Unlike other automotive components that wear out slowly, or fail without warning, headlamp failure is rather straightforward. The bulb illuminates, or it doesn’t. There is no middle ground. Servicing the headlamp unit and bulb, though, can present some challenges.

For instance, if you have a PT Cruiser, you have to remove the access cover in the splash shield in the wheel well. It helps to turn the wheel inward to access this cover.

Headlamp bulbs have a good service life, so if you buy a 2021 model this weekend, you won’t be replacing bulbs
before the end of the year. With that in mind, we’re going to concentrate on the 2015 model year. We’ll review the bulb changing procedures for several models, but concentrate on the Caravan / Town & Country.

After removing the access cover, headlamp bulb replacement involves grasping the bulb base ① on the back of the reflector ② and rotating it counterclockwise until it unlocks (see Figure 2). Then, remove it from the reflector and disconnect the wire harness ③. Remove the old bulb from the base and install the new bulb. Reconnect the wire harness, install the base in the reflector and rotate it clockwise until it clicks properly in place. Re-install the access cover. That’s it.

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Figure 2

Remember, when replacing any headlamp bulb, do not contaminate the bulb glass by touching it with your fingers or by allowing it to contact an oily surface. Shortened bulb life will result.

With the Caravan / Town & Country, headlamp bulb replacement is not much different than it is on the 300 or Grand Cherokee. Actually, access to the back of the headlamp unit might be easier than it is on those models. As with the others, remove the cover, rotate the bulb base counterclockwise to remove it, then change the bulb. Re-install the bulb base by rotating it clockwise.

When we get into replacing the HID Ballast Module and Lamp/Igniter, these tasks become a bit more complex. Let’s start with the Lamp/Igniter. In order to gain access to it, the inner splash shield must be removed. Raise the vehicle and support it safely. Remove the four push pin fasteners that attach the splash shield to the body. Next, remove the screws attaching the wheelhouse splash shield to the front and rear of the fender. Then, remove the splash shield.

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Figure 3

Refer to Figure 3. Remove the boot from the rear of the lamp/igniter. Depress the lock tab on the lamp/igniter connector ③ and disconnect the electrical connector. Next, depress the lock tab on the lamp/igniter ② and turn clockwise. Remove the lamp/igniter ① from the front lamp unit. When installing the new lamp/igniter, twist the unit clockwise until the locking tab ② clicks. Reconnect the connector and re-install the boot.

Three screws secure the HID ballast module to the front lamp unit, but in order to access the lamp unit, the lamp unit must be removed from the vehicle. And, in order to remove the front lamp unit, the front fascia must be removed from the vehicle. So, as you can see, this involves some extra time.

Without getting into great detail (refer to the appropriate service manual for step-by-step procedures), remove the necessary bolts and push pins, disconnect the electrical connectors for the fog lamps and the electrical wiring harness. With the front fascia off the vehicle, remove the three front lamp unit retaining bolts. Then, remove the four retaining from the front lamp/ fascia support bracket and remove the bracket.

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Figure 4

Pull the front lamp assembly forward to access the rear of the unit. Disconnect the turn signal, marker lamp, headlamp and HID connector, then remove the front lamp unit from its mounting. With the front lamp unit removed from the vehicle, remove the three screws ① holding the ballast module ② to the front lamp unit. Remove the ballast module (see Figure 4). The new ballast module is secured with the three screws. Re-install the lamp unit, the re-install the front fascia on the vehicle to finish the project.

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