How to Install M4 GTS Tail Lights on Your BMW

M4 & F4 Series Sequential OLED GTS style taillights (fits pre-LCI and LCI)

Upgrading to M4 GTS tail lights changes how your BMW looks at night. The animation, the sequential amber blinkers, and the clean OLED panels make the rear end look sharper and newer. If you own an F82 M4 or 4 Series coupe (F32/F36), this is one of the easiest ways to modernize the car.

This guide walks you through how to install these lights at home. It’s based on BayOptiks’ M4 GTS-style OLED tail lights—a plug-and-play kit that fits both pre-LCI and LCI cars. You don’t need special tools or coding. Just a bit of patience and basic tools.

Why upgrade to M4 GTS tail lights

Stock tail lights on the F82 and F32 are fine but plain. The GTS version has OLED panels with an animated start-up sequence and sequential amber turn signals. They’re brighter, more visible, and give your car the same look as the factory M4 GTS or M4 CS.

You can get these lights directly from BayOptiks’ M4 GTS OLED Taillights. They’re plug-and-play, so no coding or splicing is needed. Each set includes both inner and outer lamps and a factory-style harness.

Owners say the swap takes about one hour per side. The fit is snug and precise, and the animation looks OEM. You can also find other 4 Series tail light upgrades if you prefer smoked or red lenses.

Tools and materials you need

Before starting, gather these:

  • 8mm and 10mm socket wrench

  • Small ratchet extension

  • Flathead screwdriver or trim tool

  • Clean towel or soft pad

  • Gloves (to protect the lens and your paint)

  • Optional: Torx T20 or T30 bit if your car uses Torx screws

The M4 GTS tail lights use factory plugs. There’s no wiring harness to modify. The BayOptiks kit includes everything needed.

Safety and preparation

  1. Park on a flat surface.

  2. Turn off the ignition.

  3. Open the trunk and disconnect the negative battery terminal. This prevents shorts while handling electrical connectors.

  4. Lay a towel or soft mat under the rear bumper so you don’t scratch the lens or paint.

  5. Remove anything loose in the trunk that might get in the way.

Avoid touching the OLED lenses with bare hands. Fingerprints can mark them.

Step-by-Step: How to Install GTS Tail Lights on M4 / 4 Series

Step 1: Remove the trunk panels

Open the trunk. Each side of the trunk has a small carpeted trim panel behind the tail light.

  1. Pull the weather seal away from the edge.

  2. Use a trim removal tool or flathead screwdriver to pop the clips out.

  3. Slide the panel down to reveal the metal body and the back of the tail light housing.

You’ll see two or three nuts holding the light in place.

Some F32 and F36 models have a small top cover (called a drip rail). It’s held with two plastic pins. Pull them out carefully to get more room.

Step 2: Remove the stock tail lights

  1. Find the 8mm or 10mm nuts on the studs behind the light.

  2. Use your socket wrench to loosen them. Keep your other hand on the outside of the light so it doesn’t fall.

  3. When all nuts are off, pull the tail light gently outward. Wiggle it if it’s tight—there’s a small locating pin that keeps it snug.

  4. Disconnect the wiring harness. Press the clip and pull straight back.

Set the light aside on a soft surface.

Repeat the same steps on the other side.

Tip from owners: Some cars have one hidden nut deeper inside the trim. Use an extension on your wrench. Don’t over-tighten when reinstalling—it can crack the light housing.

Step 3: Clean and inspect the area

Look at the body panel and the opening where the light was mounted. Wipe away any dirt, dust, or leftover gasket material. The new GTS-style light needs a flat surface to seal against. If the old foam gasket tore off, remove it completely.

Check for moisture or corrosion on the connector. If you see any, use contact cleaner and let it dry.

Step 4: Connect and test your new tail lights

Take the new M4 GTS tail lights out of the box. Check that each lens is labeled L (left) or R (right).

  1. Connect the factory plug into the new light’s connector. Push until it clicks.

  2. Before bolting it in, reconnect your battery temporarily.

  3. Turn the ignition to position 1 and test the lights:

    • Running lights

    • Brake lights

    • Turn signals (check for sequential amber operation)

    • Reverse lights

  4. If everything works, turn off the ignition and disconnect the battery again.

Troubleshooting tip: If a section doesn’t light up, the connector might not be fully seated. Push it in firmly.

These lights are plug-and-play, so you shouldn’t see any bulb-out warnings. If you do, it’s usually just a loose connection.

Step 5: Mount the new lights

Once everything works:

  1. Slide the new taillight into place. Align the locating pin with the hole in the body.

  2. Hold it flush against the car and install the nuts by hand first.

  3. Tighten each nut evenly with the wrench. Don’t overtighten; snug is enough.

Check the gaps around the light. They should be even with the body line. If it looks off, loosen the nuts slightly and adjust.

Repeat on the other side.

Step 6: Reinstall trunk panels

Put the interior panels back the same way you removed them.

  1. Line up the trim panel tabs and push them back into place.

  2. Reinstall the clips and any plastic pins.

  3. Refit the weather seal.

  4. Reconnect the battery.

Now close the trunk and test all lights again.

Step 7: Final checks

Check that the lights sit flush with the body. Open and close the trunk a few times to ensure the seals don’t rub or catch.

Turn on the headlights. The OLED panels should glow evenly. Step on the brakes. Both sides should light up bright red. Use the turn signals and make sure the amber animation runs smoothly.

If everything looks good, you’re done.

Common installation issues

Fast blinking turn signal

If your signal flashes faster than normal, the car thinks a bulb is out. Check:

  • The connector is tight

  • The pins aren’t bent

  • The housing is fully grounded

You can also clear this with a coding app like BimmerCode. Some owners on BimmerPost note it happens rarely but is easy to fix.

Light doesn’t turn on

Swap connectors from side to side to rule out a bad plug. If both sides fail, check the fuse.

Condensation

If you see fog inside the lens, it’s usually just trapped air. Most new lights clear up after a few days of driving. If not, remove and reseat the gasket.

Extra owner tips

  • Work in daylight. It’s easier to align the lights evenly.

  • Use dielectric grease on the connector pins. It helps prevent corrosion.

  • Don’t force the trim panels. The clips are fragile.

  • Check for updates on forums like BimmerPost’s GTS tail light install thread if you run into coding quirks.

Some owners also mention that coding can enable the GTS startup animation if your car doesn’t trigger it by default. Tools like E-Sys or ISTA can handle that, but most plug-and-play sets already include it.

Maintenance tips

  • Wash the tail lights with mild car soap and water.

  • Avoid harsh chemicals or ammonia cleaners on the lens.

  • If you live in a cold or humid area, check the gaskets once a year.

  • Keep an eye on wiring harnesses when detailing—don’t pull or stress them.

OLED lights last long, but it’s still good to inspect them occasionally. If you ever need replacements, BayOptiks offers individual parts for 4 Series and M4 lighting.

Legal and safety notes

Sequential turn signals and tinted lenses are legal in most U.S. states, but local rules vary. Make sure your 4 Series GTS tail lights use amber turn signals, not red, to stay compliant.

If you’re in Europe or Canada, verify that your lights meet ECE or DOT standards before installation. BayOptiks’ lights are designed for U.S. road use.

Always disconnect your battery before removing electrical components. Don’t use aftermarket resistors unless absolutely needed—they can overheat.

Troubleshooting and coding tips

Most owners won’t need coding, but here are some cases where it helps:

  • Error message: Use BimmerCode → Front Electronic Module → deactivate “cold bulb check” for turn signals.

  • Animation not showing: In some cars, the trunk module may need to be reset (unplug the battery for 10 minutes).

  • One light out: Check grounding point behind the trunk liner. Clean it with sandpaper if corroded.

If you still have issues, check the BMW tail light retrofit guide on Scribd for wiring diagrams.

Comparing M4 GTS Tail Lights vs. Stock Lights

Feature

Stock 4 Series

M4 GTS Style OLED

Lens Type

LED

OLED panels

Turn Signal

Red blink

Amber sequential

Startup Animation

None

Yes

Brightness

Medium

Higher

Fitment

OEM

Direct plug-and-play

Coding

None

Usually not needed

Look

Basic

GTS / CS inspired

The visual difference is big. The OLED panels give a floating light pattern that looks like the real M4 GTS and CS models. It’s one of the few mods that instantly changes the car’s character without affecting performance or warranty.

FAQs

Q: Can I install M4 GTS tail lights on any 4 Series?
A: Yes. They fit F32, F33, F36, and F82 models. They work on both pre-LCI and LCI years. Just confirm your chassis when ordering.

Q: Do I need coding?
A: No. BayOptiks’ kits are plug-and-play. If you see an error later, you can fix it in minutes using BimmerCode.

Q: How long does the job take?
A: Around 1–2 hours. It depends on how comfortable you are with removing trunk panels.

Q: Can I reuse the stock wiring?
A: Yes. The new lights connect directly to the stock plug. No cutting or soldering.

Q: Do these lights cause battery drain?
A: No. The LEDs draw less power than stock bulbs.

Q: Are smoked lenses legal?
A: Smoked lenses are fine if your brake and turn signals remain visible from 300 feet. Check your local rules if unsure.

Q: Will rain affect them?
A: No. The lights are sealed with factory-style gaskets. If you notice water inside, reseat the housing or add a thin bead of clear silicone around the edge.

Maintenance and care for OLED tail lights

OLEDs are solid-state panels. They don’t burn out like bulbs. But they’re sensitive to high heat and direct sunlight.

To keep them looking clean:

  • Don’t park with the rear facing the sun for long periods.

  • Don’t pressure-wash directly into the seams.

  • Wax around the lens edges occasionally to protect the paint.

Final thoughts

Installing M4 GTS tail lights is a simple weekend project that makes your BMW stand out. The 4 Series GTS tail lights look modern, fit like OEM parts, and bring that signature GTS glow every time you unlock the car.

If you want to explore more upgrades, check out:

For more background on how sequential lighting works, see Automotive lighting on Wikipedia. It explains why these designs are brighter and safer.

And if you want to see real owner installs, check this BimmerPost thread on GTS tail lights.

Once you finish, test everything again, tighten all nuts, and enjoy the new look.

Your car will look like it just rolled out of BMW’s GTS factory.

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