What is the body control module computer?

The body control module (or BCM) is a computer which is usually located behind the steering wheel or dashboard. It controls various electrical components in the body of your vehicle. This usually includes:

  • Power windows
  • Immobiliser 
  • Air conditioning
  • Central locking

The main role of the body control module is to open/close relays that provide power to various electrical components. Most body control modules are made to specifically fit the car they come in. For this reason, it can often to be difficult to locate and install the correct part. 

Learn more about how the body control module works >


What causes body control module failure?

Old age – Like all components, the body control module soldering joints, capacitors and driver circuits deteriorate with age. An old, broken unit will normally need to be replaced.

Excess heat – Prolonged exposure to high engine heat can cause damage to the body control module. 

Water entering vehicle – Water damage can cause the body control module to short circuit, preventing it from functioning. This can also cause corrosion and high resistance on wiring harness connector pins. 

Water leaking from heater / AC unit – although not that common, we have seen a leaking heater hose or heater core drip water into the body control module computer or its wiring harness connector. As with rain water entering water from the outside, this can also cause corrosion and high resistance on wiring harness connector pins.


When might I need a new body control module computer?

Intermittent operation of electrical components – A faulty body control module can cause the connected electrical components to function intermittently, or not at all. An example of this is air conditioning which only sometimes turns on. 

Issues entering car – A faulty body control module can cause your car’s remote/keyless entry system to not work correctly. This will result in you having to use your key to manually turn the lock every time you enter your vehicle.

Battery drain – Your car’s battery may drain at an increased rate, even when the keys are not in the vehicle. This can be caused by current continuing to flow to electrical components when it shouldn’t. 

Check Engine Light (CEL) on – a major failure in the body control module computer or a component it is connected to can turn the Check Engine Light (CEL) on.


New Body Control Module Computer (BCM) – Replacement in Hamilton

Is your car in need of a new body control module computer? If so, we can help.

At Grimmer Motors, we can run diagnostic tests on your Body Control Module (BCM), determining if there are any faults that need to be fixed. If necessary, we can remove the body control module from your vehicle, replacing it with a new module or possibly a second hand one which will work with your vehicle.

For new body control module computers in Hamilton, contact Grimmer Motors today!

Please Note – we don’t generally stock or supply just “parts only” for this service. We are a general automotive repair workshop. If you are able to bring your vehicle to us, we can diagnose the problem, find and fit the necessary parts, or organise the appropriate service for you.


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