Posted by: cclngthr Nov 3 2006, 12:26 AM
QUOTE (natesi @ Nov 2 2006, 09:01 PM)
What's a "CAN line system" and a "BCM"?
ALSO (AND THIS IS A BIG ONE) if the comptuer is this picky, what would happen if you actually replaced the stock stereo? What if you replaced the stereo and used the remote lead off the new deck? In either case, would the car not start?!? That's got to be crazy man.
Thx,
-nate
http://index.php?act=findpost&pid=157522
BCM= Body control module. This is hooked up (literally) to nearly all of the circuits in the car. It has a computerized CAN (controller access network) connection to the ECU. The CAN lines go to most of the various modules in the car (power window modules to switch modules to the radio.
In the older cars, (lets use a power window circuit), power goes to a switch/relay then to the the window motor. Instead of doing this, in the HD, power is not sent to the switch on the door and then to the window motor; but a low voltage signal is sent FROM the switch to the BCM, which tells the window to roll down via a high voltage circuit.
It is possible to replace the stock deck, but getting one to fit the HUGE opening is unlikely. Hooking that up to the radio circuit (which comes from the BCM) could mean that if the new radio power draw is different than the stock deck could mean that the ECU (which is connected via CAN line to the BCM) could tell the BCM to shut down some of the BCM systems. This means the radio circuit as well as other circuits could be automatically turned off to prevent damage to the systems. In a fail safe condition, engine power could be reduced in 1/2, to a complete shut-down of the motor, creating a no-start situation.