Trunk Leak and Amplifier Water Damage Repair – BMW E90 E91 E92

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bmw e90 e92 e93 trunk leak amplifier water damage

Repair Time for Amplifier Water Damage – 2 Hours

wheel sensor replacement

The BMW Repair Guide used this 2013 M3 for the following article. To see other repairs on our site using this actual car, please click on the image below!

A major issue with the BMW E90/91/92 cars is a trunk leak around the driver’s side rear tail light that causes amplifier water damage. This situation can usually be repaired without the need of replacing the amplifier.

If you are driving your BMW E9x car and the radio starts losing speakers, starts buzzing or whining, or you lose sound all together, you most likely have a leak in the trunk that has caused amplifier water damage. DO NOT PANIC! Your amplifier water damage can be easily repaired without the need of purchasing a new unit.

In June of 2018, I picked up my 2013 E92 M3 from the body shop after two weeks of some much needed paint work. A typical summer tropical depression had just saturated South Florida for five days straight, leaving shoes and car mats covered with white marl that composes most of the southern Florida peninsula. As I left the shop, I noticed that my rear two speakers were out. As I continued down the street towards home, I hit a pothole in the road that not only knocked out the rest of my speakers, but left me with an irritating buzzing sound that would not go away…even when I turned the volume all the way down. What was strange was that the iDrive display and the stereo head unit were working fine…I just didn’t have any sound in the car.

When I pulled into my office here at the BMW Repair Guide, I decided to do a quick investigation before calling the body shop and “reading them the riot act” for frying my stereo. When I opened the trunk and pulled away the left plastic floor tray so I could inspect the amplifier, I immediately found my problem. There was about an inch of water in the driver’s side trunk well and the amplifier was partially submerged; I had amplifier water damage causing the stereo speakers to short out. Thank god I hadn’t called the body shop; a cool head once again prevails.bmw e90 e92 e93 trunk leak amplifier repair

After a lot of research on the proper way to clean submerged electronics, I was successful in repairing my amplifier water damage…which saved me over $500 and a lot of headaches. I have documented the entire process in this article. Since I obviously had to find and repair the source of the leak, I have written a second article (so as to not overwhelm the reader) on tracing and repairing a tail light trunk leak on the BMW E90/91/92.

The amplifier water damage repair is surprisingly easy. All you need to do is breathe deeply…say “Ohm” ten times with your eyes closed…and follow my directions. Namaste grasshopper.

Parts, Tools and Supplies

Parts
No parts are needed for this repair

Tools and Supplies
1/4″ socket wrench and 8mm socket
T10 torx bit
Flat blade screwdriver (small)
Metal pick
Auto trim removal tool
CRC Electronics Cleaner
Soft bristle toothbrush
Hair blow dryer
Clean lint free rags
Wet/Dry vacuum (WetVac)
Paper towels

Procedure

Amplifier Removal

  1. Remove plastic cover off of driver’s side trunk well that houses amplifier. Also remove the driver’s side tail light access cover.bmw e90 e92 e93 trunk leak amplifier repairbmw e90 e92 e93 trunk leak amplifier repair
  2. Using an auto trim removal tool, remove the first two plastic rivets securing the black trunk liner trim on driver’s side of car.bmw e90 e92 e93 trunk leak amplifier repair
  3. Grasp trunk liner and pull out from underneath trim. Fold back so you have clear access to amplifier.bmw e90 e92 e93 trunk leak amplifier repairbmw e90 e92 e93 trunk leak amplifier repair
  4. Using a 1/4″ ratchet and  8mm socket, remove the four amplifier bracket mounting bolts.bmw e90 e92 e93 trunk leak amplifier repair
  5. Remove the amplifier electrical connector by pushing down on the small button and pulling the plastic release down.bmw e90 e92 e93 trunk leak amplifier repair
  6. Use a wetvac to vacuum out all of the water from the trunk well. Use paper towels to thoroughly wipe down. Leave in a protected dry area until leak is found and repaired (Part 2 of this article).bmw e90 e92 e93 trunk leak amplifier repair

 

Amplifier Repair

Your BMW amplifier is an expensive electronic part. The repair is relatively simple…but use extreme care while performing the following steps. Be focused and patient, taking your time with each step (don’t be in a hurry). If the amplifier circuit board is dropped or cracked, you will be spending over $500 to replace it.

  1. Place the amplifier upside down on a work bench or table. Using a small flat blade screwdriver, gently pry up the four metal slide mount guides. The goal is to loosen them just enough so the slide mounts can be pulled out and the amplifier mounting bracket removed.bmw e90 e92 e93 trunk leak amplifier repairbmw e90 e92 e93 trunk leak amplifier repair
  2. Place the amplifier upside down on a workbench. Remove the six T10 screws securing the bottom plate to the amplifier.bmw e90 e92 e93 trunk leak amplifier repairbmw e90 e92 e93 trunk leak amplifier repair
  3. Remove the two black T10 torx screws that secure the electrical connector to the circuit board. These screws really do not need to be removed….but I removed them anyway just in case there was water trapped under the black plastic connector.bmw e90 e92 e93 trunk leak amplifier repair
  4. PLEASE USE CARE ON THIS STEP! The circuit board needs to be removed from the metal amplifier cover. It is held down with double sided adhesive tape. Using a 90 degree metal pick, GENTLY and METHODICALLY start tugging at the edges of the circuit board. Slowly make your way way around, using very little pressure. It took me about 5 minutes but the board finally popped off of the cover. If you get frustrated…walk away and take a breather. The last thing you want to do is pull too hard and crack the board.bmw e90 e92 e93 trunk leak amplifier repairbmw e90 e92 e93 trunk leak amplifier repairbmw e90 e92 e93 trunk leak amplifier repair
  5. Thoroughly clean the board with CRC electronics cleaner and a new clean toothbrush. Don’t be afraid to use the CRC liberally, getting it in every nook and crevice. Be careful around resistors and other electronic parts attached to the board. Take your time making sure to scrub both sides of the circuit board and the black plastic electrical connector.Trunk Leak and Amplifier Short Circuit Repair - BMW E90 E91 E92 - Part 1bmw e90 e92 e93 trunk leak amplifier repairbmw e90 e92 e93 trunk leak amplifier repairbmw e90 e92 e93 trunk leak amplifier repairbmw e90 e92 e93 trunk leak amplifier repair
  6. Using the cold setting on the hair dryer, thoroughly dry the circuit board off.bmw e90 e92 e93 trunk leak amplifier repair
  7. Spray amplifier cover and mounting bracket with CRC and scrub with toothbrush to remove water and mineral deposits. Wipe with a clean rag.bmw e90 e92 e93 trunk leak amplifier repairbmw e90 e92 e93 trunk leak amplifier repair
  8. Reassemble the amplifier in reverse of steps 1-3 above. Attach car’s electrical connector to amplifier and test. Your amplifier should be working perfectly now. DO NOT bolt amplifier back into trunk well. You do not want to reinstall until you find and fix the source of the trunk leak.

Please see our article Trunk Leak Detection and Repair – Tail Light – BMW E90 E91 E92 to fix your leak before reinstalling amplifier.

Repair finished

If you have any questions or comments, please feel free to comment on this article or contact us. And congratulations for Doing It Yourself!

The Repair Difficulty Level displays graphically how challenging the repair is, from easy to advanced. Easy repairs usually require very few tools, have short repair times and do not require jacking and supporting the vehicle. As the difficulty level rises, expect the repair to demand more time, specialized tools, and better understanding of mechanics to complete the job.