The third brake light on a Kia Forte—the CHMSL—sits at the top center of the rear for visibility and safety. If it’s dim, flickering, or dead, replacing the unit is a straightforward DIY task when you have the right part and tools. In most Forte models, you’ll access the light from the trunk area, unplug the wiring, swap in a new assembly, and reassemble.
This article walks you through identifying the correct replacement part, gathering the right tools, and performing the swap, with notes on model-year variations and safety considerations. It covers both sealed LED modules and replaceable-bulb configurations where applicable.
Identify the right replacement part
Finding the correct CHMSL for your Forte depends on model year and whether the light is an LED module or a bulb-based unit. Some Forte trims use a sealed LED CHMSL, while others may rely on replaceable bulbs behind a lens. Verify part numbers and match to your VIN or the official parts catalog.
- Check your Forte’s model year, trim, and whether the CHMSL is mounted on the trunk lid or integrated into the rear window area.
- Determine if your current unit is a sealed LED module or a traditional bulb-based assembly; this affects whether you replace the entire unit or just a bulb/socket.
- Purchase OEM Kia parts when possible, or use reputable aftermarket equivalents that list Forte compatibility by year and body style.
In short, confirm compatibility by year, body style, and whether the unit is a sealed LED module or a replaceable-bulb assembly, then purchase the correct part.
Tools and parts required
Gather these basic tools and parts before you start to avoid mid-work detours.
- Flat-head screwdriver or trim removal tool
- Phillips screwdriver
- Trim clips removal tool or plastic prying tool
- Torx driver set (if required by your model)
- Replacement Kia Forte 3rd brake light assembly (LED or incandescent, depending on your model)
- Electrical contact cleaner and dielectric grease (optional)
- Rags and flashlight
- Owner’s manual or service manual for wiring references (optional)
With the right tools, you can safely detach interior panels, access screws, and swap the light module.
Replacement procedure
The process below outlines the common steps to replace the Forte’s third brake light. Some years/models may swap the order slightly, but the core steps remain the same: access, disconnect, replace, test, and reassemble.
Sealed LED module vs. replaceable bulb
Some Forte CHMSLs are sealed LED units that require replacing the entire assembly, while older or different trims may use a replaceable bulb behind a lens. If you confirm a bulb, you’ll replace only the bulb/socket; otherwise, you’ll install a new CHMSL module.
- Open the trunk and inspect the third brake light housing on the rear deck or trunk lid.
- Remove interior cargo-area trim or panels to reveal mounting screws or clips and the electrical connector.
- Disconnect the wiring harness for the CHMSL; note the connector orientation for reinstallation.
- Remove the screws or unclip the light housing; carefully lift the old CHMSL away from the car.
- Install the new CHMSL assembly, align it with mounting holes, and secure with screws or clips.
- Reconnect the electrical connector and ensure the harness sits clear of any moving parts or pinch points.
- Test the new light by pressing the brake pedal with the ignition on (or battery connected) to confirm full brightness.
- Reinstall the trunk lining or cargo-area trim, tidy any wiring, and close the trunk.
Note: If the replacement requires resealing or involves an LED module that is sealed, you may need to replace the entire unit rather than swapping bulbs. Some models have a small service cover behind the trunk lining to access bulbs; others require removing the entire CHMSL unit from the trunk lid.
Safety considerations and warranty
Working on the rear electrical system is generally safe if you follow standard precautions. Disconnecting the battery is not always required for CHMSL replacement, but if you’ll be handling wiring near metal contacts, you may disconnect the negative battery terminal to reduce risk of short circuits. Wear eye protection and avoid pulling on wiring beyond connector limits. Replacing a CHMSL typically does not affect the vehicle’s safety systems, but check your warranty and consult a dealer if your Forte is under factory maintenance coverage.
Cost and where to buy
Prices vary by year and whether you buy a raw assembly or OEM replacement. Expect to pay approximately:
- Bulb-based replacements: $10–$40 for a replaceable bulb or socket, if applicable
- LED or full assembly replacements: $30–$120 depending on year and whether OEM or aftermarket
- Labor (if using a shop): typically $50–$100, though many owners do it themselves
Shop at auto parts retailers, Kia dealerships, or reputable online sellers; ensure you select the correct part by year, model, and body style.
Summary
The Kia Forte third brake light replacement is a manageable DIY project when you have the correct part and tools. The exact steps depend on whether your CHMSL is a sealed LED module or a replaceable-bulb unit, as well as your model year. The general process involves accessing the light from the trunk area, disconnecting the electrical connector, removing the old unit, installing the new one, and reassembling. If you’re unsure about compatibility or if the unit is sealed, professional installation is a reliable option. Regular checks ensure the CHMSL remains functional, maintaining road safety and visibility.