Brake Lights Not Working on Your Lincoln MKZ? Here's How We Fix It

Last Updated on 2025-09-09

Okay, dude - so the back lights aren't working on your MKZ? No problem, we will sort you out. Don't panic, it's nothing to get worked up over. I've dealt with this countless times and trust me, after some time and a few simple tools, those lights will be back on in no time.

So, let’s grab our tools and tackle this together as though we’re in the front yard with some tools and a drink.

First Things First – Check the Basics

You would probably be shocked how often the simple things are the one's that need fixing. But before you begin doing any crazy things like pulling trim or yanking wires, let’s check what can be done in under five minutes first.

Open the fuse box – Get your vehicle manual and look for the page where the brake light fuse diagram is located. It should either be a 10A or 15A fuse – If it is blown, you've fixed the issue already. Remember to replace it with the same amperage. If the fuse blows, we can begin to investigate further.

Checking the bulbs comes next – Open the trunk and quickly take off the taillight housing. Inspect the bulbs - If they are burned out or the filament is broken, you would need to replace it with a new one. If you like modifying your vehicle, consider using LED bulbs for a sleeker appearance and improved responsiveness. They utilize less energy and look more modern.

Check brake light switch - Using a flashlight, check under the dashboard near the brake pedal. That small switch which gets compressed when you step down (push) the brake pedal is called a brake light switch. If the switch is out of position, broken, or too slack, the lights aren't going to turn on. In some cases, it only requires small adjustment or a gentle push to reposition. If it’s worst case, swapping out a new switch is simple and inexpensive.

Still No Luck? Time to Get Dirty

If you've tried everything else, we will have to go a step further. If you have a multimeter, bring it along and let's continue solving this.

Check that multi-function switch - This is the one on the steering column that takes care of blinkers, cruise control, and wipers. Surprisingly, signals for brakes can be transmitted through that device. If it’s too old or burned, it can really stop the brake light signal. Getting to it means removing the plastic covering from the steering column. Its doable with careful self and a screwdriver. If it’s overly stubborn, it’s probably burned out and needs replacement.

Look back under the dash – This time, the brake pedal and associate switch need to be inspected in more depth. Occasionally, there is a small rubber stopper or bumper that makes contact with the switch. When that part is absent (and trust me, most of the time they are missing), there’s no pressing done on the switch and so the lights remain off. A new stopper can be used, or an improvises rubber pad can do in a tight spot.

Don’t panic. Start the wiring job with the work around the taillights. Check for any loose plugs, frayed wires, or corrosion. Pay special attention to areas where the wires pass through the trunk lid or under plastic trim – those areas tend to flex a lot and wear out faster. If you see broken insulation or green corrosion, clean that section up or rewire it.

And while you’re back there, if you’re considering upgrading the car audio system, run a few extra speaker wires or audio cables now. Since the panels are already off, it’s the ideal moment to prep for a new amp or rear sub install. It makes everything easier in the future, take my word for it.

Light Test – Let’s See What We’ve Got

Test time! We've made changes to what each station calls for, and each section requires different actions to be taken.

Grab a friend or use a heavy wrench to clamp the brake pedal. Go back and check if the brake lights have come on. They should be on and equally lit. If no, check the switch and see if it is receiving power with a multimeter. Voltage should be visible when the pedal is pressed.

Run the testes for the turn signals and parking lights - they share bulbs as is, so if one feature functions yet the other does not, that is telling. It could also be a malfunctioning filament within a dual-function bulb or a short in one of the circuits.

Yes, that sounds bizarre, and I get it, but a lit airbag or ABS could mean greater something else is wrong - in this case, electrical. Because some systems share ground wires or connections, a set of random error lights and a turned off brake light system, means you need to scan the OBD2 for codes and see what's going on.

Wrap-Up – You Got This

That’s everything you need to know about addressing brake light problems in a Lincoln MKZ. Whether it was a blown fuse, a faulty switch, or a wiring problem, you have all the tools and knowledge necessary to fix it.

Don't worry about it too much if you have done all of the above steps and still do not have functioning brake lights. Oftentimes this problem is hiding deeper in the BCM (Body Control Module), and in this case, will require a specialist with factory diagnostic tools.

This guide should be more than enough to get you there, but, in rare cases, issues may arise.

If you are looking to upgrade to LED lights or are interested in installing an audio system while the rear is disassembled, feel free to reach out to me. If we decide to turn it into a weekend project, I can even bring the beer.