Mercedes Key Fob Not Working due to Faulty Antenna Amplifier

Is your Mercedes-Benz Key Fob Not Working due to Faulty Antenna Amplifier? Learn how to fix the problem by replacing the faulty Antenna Amplifier.

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Problem

The key will only lock and unlock the doors if you are very close. The red light on the keyfob does turn on when you press the lock or unlock problem.

Solution

One possible cause is a blown fuse for the antenna amplifier alarm.

If you replace the fuse for the antenna amplifier and it keeps blowing, the issue may be the antenna amplifier.

What you will need

• Mercedes Antenna Amplifier

How to replace the antenna amplifier

The antenna amplifier is mounted on the C-pillar driver’s dire on sedans such as E-Class and C-Class vehicles. On SUV vehicles such as ML350, the antenna amplifier is mounted on the lift gate and requires the removal of the plastic trim from the lift gate.

Below are instructions on how to replace the antenna amplifier on an E-Class.

1. Disconnect the battery.
2. Open the rear door.
3. Remove the weather strip from the door.
4. Remove the cover from the C-pillar. It is held in place with plastic trim. It may require a little force to come out. Picture of plastic retainer that holds this cover in place.
5. Locate the antenna amplifier. This is typically a green box mounted on the frame. It may also be a black box.  It is on the driver’s side behind the rear windshield. If you have an SUV, it may be mounted on the liftgate.
6. Unplug the electrical connectors from the antenna amplifier.
7. Remove the two 10mm nuts that secure the antenna amplifier to the frame.
8. Remove the old antenna amplifier. Install the new antenna amplifier to the frame, tighten the 10mm nuts and reconnect all the wires.

Notes

• Sometimes the issue is not the antenna amplifier itself but the wires going to it that may have shorted.
• When purchasing a replacement antenna amplifier, we recommend buying a part with the same part number. You can also call the dealer and check if a newer part is available.

Related Part Numbers

Here is a list of part numbers for various Mercedes-Benz antenna amplifiers.

• 1708200389
  • 98-00 MERCEDES SLK230 ANTENNA AMPLIFIER
• 2168200489
  • Antenna Amplifier Booster Mercedes CL600 CL63 CL65 C216 2007-13
•  A 164 870 24 89
  •  GL550/GL450/GL350/GL320/ML550/ML350/ML320/ML500/
• 2218208389
  • 2007-2009 MERCEDES S550 S-CLASS W221, ANTENNA AMPLIFIER

There is just a few part number for the Mercedes-Benz antenna amplifier. Call your dealer or remove the old part to find the part number that will fit your car.

We hope you find the Mercedes Key Fob Not Working due to Faulty Antenna Amplifier guide helpful. Check these troubleshooting and repair guides for more help on your Mercedes-Benz.