So for the vehicle type (I think thats what they call it) you choose N, I choose K due to being a 4x4

I'll give that a try,

Using K mine only shows 2004 but I'll choose N and see what I get, thanks for the info Bronx

Neal

 

You have to go into SPS to request the info from the module your wanting to program,
going to BCM first will only give you the ID and calibration info, this is what it looks like to me

Neal

 

Finally an update on this. The rear access alarm was happening more often. It would chime constantly. I went over the bcm circuit board with a fine tooth comb and found no physical defects. The first thing I tried was to swap a bcm from a Tahoe, which I didn’t get too far with. Hummer would start and then die. At the time I didn’t know it was a security issue. Nevertheless it was a dead end because when I tried to upload calibration from tech2 after tis2000 update, it failed to program. I tried pass through mode also. So I put the original bcm back in and continued getting alarm. Next I tried swapping an Escalade bcm, this time I did a security relearn and Hummer stayed running. I had a airbag light, which ended up being something along the lines of software mismatch. Hummer would drive and I thought I would update bcm and I’d be good to go. Not the case. I tried to upload to Hummer and programming failed part way though again. Now Nothing would work, windows won’t work, radio is stuck on, no interior lights, 4wd alarm, starts and then dies. Bricked I believe is the term. Back to square one. Did some more research and learned about eeprom chips. There’s no mileage on the bcm so I thought I could clone the eeprom from my original bcm and put my vin in the Escalade bcm. This also failed. The clone was successful though No change from previous. I can see my vin on the replacement bcm eeprom using an ic programming software. Maybe I would have had better luck if I cloned eeprom before I bricked bcm idk. So also a dead end for now. I thought I might need an exact part number match for the programming to work. So MixManSC and I compared bcm part numbers and ours are different, not sure if it matters. Someone with higher level electronic knowledge might be able to clone bcm somehow. Idk. Out of ideas, I ended up fixing my original bcm. Rear access alarm comes on when circuit is grounded. I opened bcm again. I attached one meter lead to black wire with white stripe (ground) on bcm and the other lead to rear access pin and got around 80 ohms. There’s a row of tiny caps on the top and bottom of board. I desoldered corresponding cap to rear access pin and replaced with one from Escalade bcm. Installed and did security relearn again and I have 100% function again. Rear access alarm works correctly now. So if we ever need a bcm idk what we would do. I’ve read that a new bcm that is virgin would be the only way a reprogram would be successful.

 

fastNYsix very impressed with you patiant and meticulous work done on your BCM and what you've found makes perfect sense, surface mount capacitors are prone to that kind of failure.

The different BCM P/Nos may represent different "build levels" i.e. the PCB layout, circuit and supporting software structures are different. This is maybe why updating software or cloning is so difficult, there's also the "fraud" angle.

Probably both EEPROM and CPU (or CPU's) get re-programmed, this why they can become "bricked" when loaded with the wrong software.

Its also good that the other members supported you with this.

Again very well done!

 

Excellent work as ocean mentioned. Glad to hear you found the root of the issue! There is little info on the body control modules online in regards to reprogramming them. I know the 99-02 truck ones are different than the 03-07 ones and I've read that before that one or possibly both might only be able to be fully programmed once. Then again I know certain things can be changed on them for both year ranges like enabling and disabling fog lights which I have done on a Tahoe but on ours, even though they have the fog light capabilities, you cannot add/enable them. One I never did try was to take an H2 BCM, put it in a Tahoe (or give it a Tahoe VIN) and see if I could enable the fog light functionality that way. There is ONE guy online who has figured them out Chris White - https://www.whiteautoandmedia.com/. He is the only person I'm aware of who has fully figured out how to customize a GM BCM and can add features, customize text that shows on the dash display, etc.

 

Thanks for the kind words. I wonder if there's a way to erase the bcm or at least make the tech 2 think its a new unit. Maybe the silver lining is these things rarely fail, that's why there's so little info about them. How would the dealer do this? There are no more new units.

 

right before programming the tech 2 asks if it is from your vehicle or another. something to that extent. did you do it as new to vehicle? it then asks to confirm vin or change it

 

I tried both ways. Tis2000 asks if you want to either reprogram or replace/program. The first time with tahoe bcm, I did the replace/program option without doing security relearn. Which locked up at the hummer. Then I tried pass through and locked up. Does GM think they're funny by adding an exclamation mark next to "programming failed", to further rub it in my face. The second attempt was with Escalade bcm, which I did the security relearn first. I tried to do the reprogram and got a message that said something about mismatch/aftermarket software. So then I did replace/program, and locked up that bcm also at the hummer. I tried to download sps to tech 2 after lock up and got lines of asterisks on the one page that shows the modules that were downloaded. Then when I go to tis2000 to program, there's all asterisks on the left side of screen and on the right hand side of screen are the updates. Which is why I assume the reprogram wouldn't work, because of asterisks. The tis2000 download to tech 2 was always successful. Maybe I have an issue with tech 2 or hummer. I don't think its an issue with hummer because I'm communicating with all the modules.

 

when i swapped my cluster with a 2003 denali cluster i was able to unsolder the eprom and swap it in. it kept all my data and mileage.

 

I dont think its your Tech2 or your Hummer. I've seen people run into similar problems on GM trucks and SUV's when trying to reprogram a BCM and more than once they gave up and bought a new virgin one and it programmed perfectly fine.