Hello, i am including a service info please read, i think this is what you are asking about.
Your vehicle is equipped with an automatic lock/unlock feature which enables you to program your vehicles power door locks. You can program this feature through the driver information center (DIC), or by the following method.
Programmable Locking Feature
The following is the list of available programming options:
Mode 1: All doors lock when the transmission is shifted out of Park. Mode 2: All doors lock when the vehicle speed is greater than 8 mph (13 km/h).
The following instructions tell you how to change the automatic door lock mode. Choose one of the two programming options listed above before entering the program mode. To enter the program mode, do the following:
You can exit the program mode any time by turning the ignition to RUN (the doors will automatically lock and unlock and the horn will chirp twice to indicate that you are leaving the program mode). If the lock/unlock switches are not pressed while in the programming mode, the current automatic settings will not be modified.
Programmable Unlocking Feature
Mode 1: Drivers door unlocks when the transmission is shifted into PARK (P).Mode 2: All doors unlock when the transmission is shifted into PARK (P). Mode 3: All doors unlock when the key is removed from the ignition.Mode 4: No automatic door unlock.
The following instructions tell you how to change the automatic door unlock mode. Choose one of the four programming options listed above before entering the program mode. To enter the program mode, do the following:
Very good, our vehicles of today are not far off from being rocket science!!!! after doing some more research, i have come up with a service documents for your concern. the door locks operation is programmed into the body control module. body control module is a simple computer that works off a serial data line that communicates with the door modules. oh yes the door switches that are mounted in the door are actually working computers. the switches work like a key board for a pc. they are simple data imputs to the bcm and door modules.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Some customers may comment that they are unable to override the automatic door locking feature. In prior model years, customers were able to select "Doors Lock Manually" from the DIC. However, starting in the 2005 model year, this selection was removed.
Since the 2005 model year, all BCM's (Body Control Modules) are programmed from the factory to allow two personalized door lock settings:
Setting 1: All doors lock when the transmission is shifted into gear.
Setting 2: All doors lock when the vehicle speed is greater than 8 mph (13 km/h).
Hello, lets start with the safety concern. I can see your side of the concern. but here are the facts as i know them. when we build a vehicle, there is allot of thought and testing that go into safety.but here is the kicker we still have our legal system to deal with. why some changes of operation take place. originally gm built the vehicle with many programable features. thought being let the customer choose the way they want there vehicle to operate. that is all fine and dandy, until something happens and there is a big lawsuit!!! and then it is back to the drawing board. lets make the functions less changeable. taking the risk factor out of the picture. What most people dont stop and think about. we as car builders, have to think about the legal end.
back to the task at hand. as far as using a 04 bcm, possible but creates a whole new set of problems. bcm are originally set up with some basic information and then is finished programed at the dealer for each vehicle. Oh and the bcm are VIN stamped. as a dealer, we have only limited ways we can program,. when we set up a bcm for a vehicle we use a scan tool and a pc link to gm. and we simply program by answering software questions by a yes or a no.
The comment about trying to fool system with the mph. there is where things get real tough. The data line that connects every module on your vehicle caries information back and forth between modules. kinda like the internet. The power control module is in charge of the mph function. so the pcm just simply talks to the bcm and says hey i am 8 mph lock the doors. the same hold true for the park and neutral. the information is sent via of data line to the bcm, hey bcm i am in gear lock the doors.
Our vehicles of today have become a rolling internet. some vehicles have a small number of modules say about 5 to all the way up to 28 modules. the point being all the modules have a specific job to do, but share all their information with other modules to perform other tasks. even the radio in your vehicle is on the data line it has other roles in the system other than playing tunes.
as far as diagram's and repair information, the last i heard there approx. 15,000 pages of documents per vehicle. if there is something specific you need i can help. but if you really want to have access to all the information. you can still buy repair manuals thru your dealership.
Hello again. let me first say it has been a real pleasure chatting with somebody like yourself. you seem to have a understanding on what actually happens with our vehicles of today. to answer your question about the park switch. there is mechanically operated switch mounted on the side of transmission, which is operated by the shift linkage. here again same principle, the switch is merely a input to the the power control module. once a action has taken place by the shifter the prndl switch say to the power control module i am now in gear, the pcm in turns tell the bcm, hey we are now in gear, the bcm now says to the door module hey we are in gear do something with the door locks.
There are some after market company that you can purchase service information on any vehicles. such as alldata, and there are some others. you can purchase several different ways. you can buy a one time c/d pretty pricey, some where in the 1000.00 range. or you can purchase by paying a monthly service fee. pretty pricey too.
your vehicle works off what they call a uart bus line. now this system is really getting out dated. now we are using gm lan high speed data bus lines which uses two serial data lines. we have to use a special adapter for our scan tools to slow the information down, so we can read what are the systems are doing. who knows what will happen in the next 10 years. look out George jettson!!!
here is a wiring diagram on how some of the bus line works.
Ok, looking forward to hear from you!!!