Owners of other Mazda vehicles such as the CX-3, CX-30, CX-7, CX-9, Mazda3, Mazda6, MX-30, MX-5 Miata, Mazda2, CX-4, CX-8 and BT-50 may also find these DIY instructions to be helpful.

The compatible replacement light bulb part number is WY21W (also known as the 7440NA bulb).

If you'd like to have brighter rear turn signal lights that will also last much longer before burning out like the traditional incandescent bulbs, install some WY21W LED bulbs.

The tools needed to access and replace the bulbs include a small flat head screwdriver or a plastic pry bar tool and a standard Phillips head screwdriver.

Note - On this 2019 CX-5 the brake (stop), parking light, reverse (back-up) and side marker lights are LED bulbs that should last the life time of the vehicle.

The first two steps are to open the tailgate door for the cargo area and move to the side of the vehicle with the burnt out light bulb.

Locate the rectangular shaped access cover on the inner edge of the tail light housing.

Insert the blade of the flat head screwdriver or the small plastic trim panel removal tool into the notch at the bottom of the access cover and gently pry it out.

Set the access cover aside in a safe place.

Loosen the two screws by turning them in the counterclockwise direction with the Phillips head screwdriver.

The tail light housing is still held in place by two friction fasteners on the front outer part of the assembly.

There is a plastic peg (or "spike") inserted into a grommet and a slot that slides over a button head.

Carefully pull the tail light housing straight off the rear corner of the SUV.

If you have trouble removing the housing, try gently wiggling it back and forth while carefully pulling it straight off.

Turn over the housing to access the bulb socket.

Rotate the base of the bulb socket 1/4 turn in the counterclockwise direction before pulling it straight out of the housing.

If the old light bulb was recently turned on, be careful when you remove it. The old bulb might still be hot enough to burn your fingers.

Pull the old light bulb straight out of the socket.

If you have trouble removing the old light bulb due to corrosion (rust), sand or other debris, put on some thick gloves and try very gently wiggling the bulb back and forth while pulling it straight out.

Push a new WY21W (or a 7440NA) natural amber colored light bulb straight into the socket.

If you are installing a traditional incandescent bulb, wipe it clean with a paper towel and some rubbing alcohol.

Any grease, oil or dirt left on the new bulb may cause a hot spot and could lead to the bulb burning out prematurely.

If you'd like to have brighter rear turn signal lights, install some compatible replacement WY21W LED units.

Reinsert the bulb socket into the housing and rotate it 1/4 turn in the clockwise direction.

Double check that the bulb socket is securely installed in the housing.

Line up the peg (or "spike") and the slot on the back side of the housing with the grommet and button head on the rear corner of the vehicle.

Slide the tail light housing back into place.

Try to avoid over tightening the two screws to prevent from cracking the plastic inner edge of the assembly.

Line up the plastic trim cover with the opening.

First, reinsert the two tabs on the top edge of the cover into the opening.

Make sure the access cover is securely in place.

To test the new rear turn signal light bulb, activate the hazard signals.

Tip - If you installed an LED bulb and it doesn't work, try removing it from the socket, rotate it 180 degrees and then push it back into the socket. Some LED bulbs are "polarized" and will only work when the "+" positive and "-" negative electrical contacts are in the correct orientation.

Please check out all of my 2017-2022 Mazda CX-5 DIY Repair & Maintenance Guides.