The Body Control Module (BcM) – Dave’s Garage

lucas body control module BCMAbsent any questions this month, I’ll tell the tale of a recent repair to my Chrysler minivan. I have had problems with the Body Control Module for the past few years. The BCM is the “brain” of the vehicle, and it’s function is the control of all things electrical in the vehicle. This part is vehicle specific, and stores all the vehicle data, such as the mileage on the odometer and the Vehicle Identification Number.

This problem first presented itself with the wipers, lights and door locks randomly going on and off, regardless of the switch positions. This would happen whether the key was on or not. I was always able to “fix” the problem by rebooting the BCM. Rebooting the BCM is accomplished by disconnecting the battery overnight. Simply disconnecting the battery for a few minutes or a few hours would not work. Sometimes the battery would have to be disconnected for a day or two for the reboot to be successful. After a successful reboot the repair would usually last for several months, but the problems would always reappear. Recently, the wipers and the low-beam headlights ceased to function. I suspected the BCM, but a re-boot did not yield a fix. I checked the usual suspects, fuses, relays, bad grounds, etc. I quickly determined that there was no power going through these circuits. I thought I should check the wiper stalk, which is also the high beam/low beam switch. Imagine my surprise when I took the switch out, and discovered the Lucas Electric logo stamped on to the switch. You know, Joseph Lucas, Ltd. Birmingham, England- the punch line of many a joke about the poor reliability of English cars.
This switch actually tested out fine, so the BCM was once again suspect. Remember, the BCM is unique to the car in which it is installed. Even If I was lucky enough to find the same year, make and model van in a salvage yard, the BCM still holds the identity of the car it is built with. The VIN number and mileage are both stored in the BCM. The cost of a BCM through a dealer costs well over a thousand dollars, and the part needs to be programmed to the vehicle at an additional cost.

A google search proved to be quite productive. I found an outfit in Michigan that has identified the weakness in Chrysler BCMs and rebuilds them with improved components. All they need is the year, make, model, mileage and part number on the BCM, and they send you a rebuilt BCM already programmed for your car. While not cheap (at $250-including shipping…) it is less than a quarter of the cost, better quality and much faster turn around time than the dealership.

What did I learn from this experience? With today’s cars, there is less of a difference between foreign and domestic cars. With world wide vendors supply-ing the OEM parts market, there is no telling what you will find. I was stunned to find a Lucas switch in a Chrysler minivan.

It also pays to use the Internet when doing automotive repairs. Finding the outfit in Michigan that repairs Chrysler Body Control Modules probably saved me over a thousand dollars.

Please email all inquiries to: Dave
or snail mail
32 Turkey Hill Road
Richmond VT 05477

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