Brake light not working

The bulbs are led and the whole CHMSL must be replaced as a unit. You have to open liftgate take off panel then spoiler here are pics.

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Need to remove liftgate panel see diagrams

Here are the wiring diagrams and a guide to help you see what the problem is. The power to the third brake light comes from the TIPM and there are many fuses that run it. First see if the brake light is getting power at the light.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

then check the fuses,

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Here is the fuse location and the diagrams (below)

If all of the fuses are good then its most likely the TIPM is going out which they had problems with. A shop will need to program the unit unit in.

Please let us know what you find.

Cheers, Ken

I doubt the light has anything to do with the check engine light. Have a professional scan for codes because this may be a tpim module problem. The brake light switch sends power to the tpim then to the light. Only a local professional can scan for this. Also check engine problems will also come up.

That is what a tpim module is, the car's computer and it runs the third brake light that is why it does not work.

You can see by the picture it may already be wired direct, so see if power is going to the light then backtrack wire to see if it is broken. If no power, if power is there then check the ground wire which is in lift-gate.

If after replacement the bulb does not work, I would recommend checking the contacts in the bulb connector. The connectors will sometimes develope burn marks on their contacts where they meet the bulb. Look in the bulb connector. Do you see any burn marks, corrosion, etc? If you do you can try using a small piece of fine grit sand paper to clean up the contacts. Also pry the contacts out slightly to make sure they are making a solid connection. If this does not work you will need to check if there is voltage to the connector. This will require a voltage test light ($10) or a multi meter ($50+) from your local auto parts store. Using a test light, connect it to a good ground and with the brake pedal depressed touch the test light tip to the positive contact in the bulb connector (you can touch it to both if your not sure which one it is). If your test light lights up you have power at the connector, if not you will need to trace the circuit back to where you have power.

Check tosee if wires leaving brake switch are sending power then check upper light and see if they are getting power

Check for blown fuses and the brake light switch which is on the pedal.

The highmount brake lamp and lower brake lamps get voltage from the same fuse. So I don't think the problem is the fuse.

At the lower brake lites, white wire with tan tracer is voltage, so use a test light and check for voltage, brake pedal depressed, if no voltage we will have to backtrack circuit. There is a splice on that circuit, may have to find that splice if no voltage.