Owners of other General Motors vehicles from Chevrolet, GMC, Cadillac, Buick and Holden such as the Trax, Equinox, Traverse, Blazer, Tahoe, Suburban, Sonic, Cruze, Trailblazer, Spark, Malibu, Impala, Volt, Bolt, Corvette, Camaro, Silverado, Express, Regal, LaCrosse, Cascada, Encore, Enclave, Envision, Canyon, Sierra, Terrain, Acadia, Yukon, XT4, XT5, XT6, Escalade, CT5, CTS, XTS, CT6, ATS, Astra and Commodore may also find these DIY instructions to be helpful.

The compatible replacement miniature wedge base bulb part number for all three lights is 921 (also known as W16W).

If you would like to have a brighter 3rd brake light or cargo bed lights, install some 921 LED bulbs.

The only tool required to access and replace the bulbs is a Torx T20 star bit screwdriver.

The first two steps are to lower the tailgate and climb on to the cargo bed.

Loosen the two screws on the light housing by turning them in the counterclockwise direction with the Torx T-20 screwdriver.

Gently pull the light housing straight off the back of the passenger cabin.

If you have trouble removing the light housing, use a small plastic pry bar tool to carefully separate the housing from the vehicle.

An optional step is to disconnect the housing from the electrical connector.

Push in the release tab on the power plug before sliding it straight out of its socket.

If you have trouble removing the old light bulb from the socket due to rust or debris, try gently wiggling it back and forth while pulling.

Try to avoid using excessive pressure on the old light bulb to prevent from having it break and cut your fingers.

The OEM (original equipment manufacturer) light bulbs in this 2019 Colorado LT were marked as part number W16W which is the same as the 921 bulbs.

Clean the new bulb with a paper towel or a micro fiber cloth.

If there is any grease or oil on the new bulb, it can cause a hot spot and lead to the bulb failing prematurely.

If you would like to have a brighter 3rd brake light or cargo bed lights that will also last a lot longer before burning out, install some compatible replacement 921 LED bulbs.

Re-insert the bulb socket into the housing and twist it 1/4 turn in the clockwise direction to secure it into place.

To replace the other bulbs, repeat the process.

Rotate the bulb socket 1/4 turn in the counterclockwise direction, pull out the old bulb, push in the new bulb, clean the bulb, re-insert the socket into the housing and rotate it 1/4 turn in the clockwise direction.

The electrical connector should "click" securely into place.

Line up the light housing and push it back into place on the rear of the passenger cabin.

Try to avoid over tightening the screws to prevent from cracking the plastic light housing.

To test the new light bulbs, have an assistant step on the brake and press the "Unlock" button on the key fob to activate the cargo bed lights.

Tip - If you installed LED bulbs and they don't work, try removing the bulbs from the sockets, rotate them 180 degrees and push them back into the sockets. Some LED bulbs are polarized and will only work when the "+" positive and "-" negative electrical contacts are in the correct orientation.

Be sure to write down the bulb change in your truck's service records.

Please check out all of my 2015-2019 GM Chevrolet Colorado DIY Repair & Maintenance Guides.