Case Studies

Mini Cooper – Footwell Control Module (FRM) Body Control Module and Water Leaks – Service Info

Mini Cooper – Footwell Control Module (FRM) and Water Leaks
“You have water in your car”
– that very phrase should be enough to strike fear into the heart of most car owners, water is not the friend of today’s highly electronic and computerized cars, and few suffer more from it than the beloved Mini Cooper.

If you have wet carpet on the driver’s side floor, or have a damp mildew smell in your vehicle. Check the driver’s floorboard or carpet for water saturation. The carpet pad on the Generation 2 Mini Cooper is almost 2 inches thick. So a lot of water will hide under the carpet before you will notice a problem. We have discovered water migrating into the vehicle, under the carpet, and then flooding various expensive electronic control modules.

These control modules are located in the driver and passenger side foot well.
Unfortunately, water and electronic components don’t get along. And the water seems to win the battle every time.

Location, Location, Location
The Mini Cooper FRM lives at the bottom of the driver’s side A-pillar behind an interior trim panel. Due to several contributing factors (environmental, certain US States’ wintertime road treatment, vehicle design configuration, and age), over time, the FRM could become susceptible to corrosion from water entry.

There are a number of water leak sources on Mini Coopers, which we mention and discuss in detail below. Suffice it to say that any dampness discovered in the car, on the carpeting, especially on the passenger side front floorboard or carpeting, needs to be investigated and corrected at once.

Signs of Failure
The footwell module failing is a common issue in both BMW and MINI models, its job is to receive signals from sensors across the vehicle, mainly controlling body aspects such as electric windows, air conditioning, heating, lights (interior and exterior) as well as exterior mirrors. FRM failure can be caused by jump starting, incorrect charging, and water infiltration (very common on Minis) damaging the sensitive electrics.

A common sign that there is an issue with the footwell module is that you will notice issues with one of these elements, such as the heater not working, lights not turning off, or not turning on. You may find you have intermittent issues with your windows not opening or closing. You can often find communication problems on the vehicle’s CAN Bus network, especially on the K-Line.

What Happens
For Mini Coopers equipped with a sunroof, after a multi-year period involving large temperature changes, multiple freeze/thaw cycles can cause the vehicle’s sunroof drain hose to become damaged, loosen, and eventually detach from the drain pipe within the A-pillar, which could allow water to enter the vehicle interior.

In certain US states, large amounts of road salt may be utilized during their wintertime road treatment activities. If water were to enter the interior, then in combination with road salt that may be present in the footwell, this could create an electrolyte solution, which causes extensive corrosion on both electrical pin connectors, and the module itself.

Other Mini Cooper Water Leak Sources

  • The passenger side windshield cowl cover seal deteriorated, and not properly sealed to the windshield.
  • Battery cover plastic hatch cover broken or missing.
  • Sunroof drain tubes clogged with debris or disconnected (this occurs with clogs and cycling).
  • Improper windshield installation (not enough adhesive on the glass to seal out water.)

The usual path of correction consists of diagnosing and correcting the water leakage. The replacement of the FRM, which requires coding and programming of the new unit (the repair is only possible on lightly wet units) and is our first choice for a durable correction, heavily corroded units must always be replaced.

Also, most, if not all of the electrical pin connectors in the wiring harness for the FRM will require replacement, sometimes even the plastic connector housing. Additional work may be needed on the wiring, depending on the level of corrosion present. The cost of this can vary from $1,200 to more than $2,200 depending on the extent of damage found.

An Ounce Of Prevention
Check, or have checked regularly your vehicle’s cowl, sunroof, and other body drains. This is doubly true if the car lives outdoors, rather than in a garage. You’d be amazed at how quickly the “schmutz” builds up in the drains and lines. Pine needles, leaves, road dirt, pollen, you name it.

Cars that live outside should have drains checked, and cleaned as necessary, ideally every quarter. As my mother used to tell me, “An ounce of prevention is worth it pound of cure.”

If you’re an Atlantic Motorcar customer, we’re going to be keeping an eye on this for you (Doesn’t hurt to remind us if you’ve noted any water inside your car, odd, musty smells, etc.). If you’re not, make sure it gets done, kind of like that old bromide about voting, “early and often”. 😉

Our Goal For You and Your Car
Our goal is to save you money, not spend it. This is why each and every car that we service gets a free Courtesy Maintenance Inspection during its first visit. Our goal is to let you know about the small problems before they become big ones. Right now we have a number of customer cars with well over 200,000 miles, and several approaching 300,000! And these cars are not just limping along – most look and drive pretty much the way they came out of the showroom.

Proper maintenance is an investment in the life of your vehicle.
Knowing, not just doing, but actually knowing and understanding the difference, makes all the difference.
Be sure your car is properly loved, our professionals will attend to both you and your car’s needs.
Atlantic Motorcar…Extraordinary Service for Extraordinary Cars, just a phone call away, (207) 882-9969.


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