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Q: replacing BCM on 2000 Chrysler LHS

I am sure by information I received through this site that the BCM is bad. I did a power reset by disconnecting the + battery cable at the positive jump start terminal. That did not change the symptoms. I bought a used BCM but I have read that the BCM must match serial number or a model number?? Any truth to this? Also, I was told if I put in one that does not match my car, it will disable some systems and may never start until a dealer recodes the computers. Please provide some truth to this.
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This is true that you must replace the BCM with the same Model year and Part number. Also if the VIN programmed in the BCM does not match your vehicles VIN, many of the BCM functions will not work and yes, if your vehicle is equipped with a vehicle theft alarm, it will not start Here are some of the things the BCM controls.
The body control module (BCM) supplies vehicle
occupants with visual and audible information and
controls various vehicle functions. To provide and
receive information, the module is interfaced to the
vehicle’s serial bus communications network (the
Programmable Communication Interface or PCI
bus). This network consists of the powertrain control
module (PCM), the memory heat seat/mirror
module (MHSMM), sentry key immobilizer module
(SKIM), the transmission control module (TCM),
the electro/mechanical instrument cluster (MIC),
the optional overhead travel information system
(OTIS), airbag control module (ACM), optional antilock
brakes (ABS), the radio and the optional
automatic temperature control (ATC) display head.
The (BCM) is operational when battery power is
supplied to the module, ignition switch power is
needed for ignition switched functions.
The body control module provides the following
Automatic headlamp and fog lamp
A/C switch status/evaporator temperature status
BCM diagnostic support
Central lock and unlock (VTSS only)
Climate Control (Automatic and Manual) system support
Door ajar switch status
Door Lock Inhibit (key in ignition or headlamps/park lamps on)
Electronic Odometer Support
Fog Lamp Control
Headlamp multiplexing control
Headlamp, Park & tail lamps with battery save feature
Headlamp Time Delay
Illuminated Entry with “fade to off”
Interior lighting with battery save feature
Mechanical Instrument Cluster (fuel level, dim data, odometer & warning chime) support
Memory system (LHS and 300M)
Overhead travel information system
Power door lock multiplexing control
Rear Window Defogger Control
Remote Keyless Entry with Panic Mode
Remote power deck lid release
Rolling door lock control (customer programmable)
Sentry key immobilizer
Speed proportional steering
Vehicle Theft Security System
Wiper Control (speed sensitive with return to park)
The BCM receives information over the PCI Bus
from the PCM in order to support certain features.
The required information is as follows:
² Engine RPM
² Engine Temperature
² Injector on Time and Distance Pulses
² Vehicle Speed
² Charging System Failure, Engine Temperature Limp-In, VTSS Arming Status
² Engine Model
² “Check Engine” lamp status
The BCM provides the PCM with information on
the A/C switch status, battery temperature which is
determined by the ambient temperature sensor and
the “OK to Start” or VTSS status.
If the BCM is replaced, the VTSS must be enabled in the new BCM via the DRB lll®, in order to start the vehicle.
Thanks. I have had a mechanic trying to tell me the ingnition switch (electrical parts) is bad. I have more symptoms than the position on the switch is identified with.
You're talking about the car's computer module or brain. What you've been told is true. If the computer is going bad, it must be replaced with a new one, a used one will not work. This happened to my car and my mechanic couldn't fix it; I had to take it to the dealer. They have to reprogram the new computer to match all the information in your old computer. This repair runs around $750 where I am from.
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