So around 3 months ago our key fobs decided to start acting up as others with similar experiences have posted on this forum. We have an '06 with only 113,000 on it (yes we baby it). Started with not locking or unlocking the vehicle at distance. Then it would only lock or unlock near the BCM. Now it does nothing and you have to manually open the drivers side door. After spending copious amounts of time reviewing these forums for possible solutions, I figured I would post and see what advice people may have regarding this particular instance. I'm going to list out all the steps we have completed in the hopes we can narrow down the issue and what to do to rectify it.

1. Replaced the battery terminal connectors with aftermarkets.
2. Replaced batteries in both fobs.
3. Replaced the fob shells.
4. Removed and cleaned the BCM antenna connection.
5. Removed the BCM and cleaned the connections. We had the sunroof drain issues years ago (over 8+ years) but the BCM appears to be in great condition. No corrosion present, no dirt, no dust. All the connections still looked good.
6. Replaced the fuse for the BCM.
7. Checked the C105 and C106 grounds. No corrosion present.

The TPMS on the dash does go off every once in a while but I would expect that on every trip if the BCM antenna wasn't working or receiving. New TPM sensors were installed in 2021 with the new rims and tires. We did have the windshield replaced a month or two before this started due to a nasty rock strike but there have been no leaks into the floorboard. Is there something in the dash they could have hit or knocked loose while replacing the windshield? I don't know. This is our third windshield and we had no issues years ago with the first replacement.

I'm at a loss at this point. I don't necessary want to chase ghosts and throw money way on things that simply do not need to be addressed. Is the BCM actually going or has it simply lost programming with the fobs? What would be a good place to start? I thought about reaching out to a locksmith and trying to reprogram the keys as the next step.

Any advice would be welcome.

 

My '07 is closing in on 94,000miles
I did some inspection on the bcm board/antenna connection a couple years ago which looked good yet I cleaned the board inside along with the bulkhead/antenna connections/contacts inside&out.
After all the time I spent trying to revive the bcm antenna I decided to leave it alone since the bcm is still working properly.
Currently:

1. I have 4 dead TPMS sensors in my tires that have plenty tread remaining and NO TPMS WARNING on the dash!
2. I have 4 fobs programmed that don't work!
3. I still carry a key for ignition/drivers door lock + fuel cap lock key:

 

You can chase the Gremlins with no guarantee of success, and even if you get the OEM fobs to work, they have a limited range.

Get an aftermarket remote start installed by a reputable local shop. You will have 3-4 times the range of OEM fobs, and you can start the truck. Then throw away or Ebay your dead fobs.

 

I thought there was a thread about lengthing the antenna on BCM and rerouting it out side dash cover? 🤔

Props to another hummer owner for this:
Ok....received the new BCM antenna from GM. Part number is 22936091, just to find out the plug is slightly different, I had to file off the 2 little proud spots on the BCM plug to get it to plug in. Once plugged in, I could get the Key Fob to program and work,, I would consider the range to be kind of weak compared to the newer fobs of today {works all the way around the truck, but not from more then a car length away}. Plugged the old antenna back in {which had not worked at all} it now works with REALLY limited range {pretty much just in the truck} ..........So with the new antenna it works better then the original, although I'd still say limited to a car length away. I really don't know how well these things worked when new, the BCM probably has lost a few steps over the years as well I'm guessing

video helps:

 

I was chasing the same issue last year and earlier this year, and followed all the same steps as you, but also tried a replacement BCM antenna I got from the local pull n pay and spraying down the BCM circuit board with CRC and letting it dry out.

The thing that fully resolved my issue was when I found and cleaned corrosion in the connector in the harness that runs aft and below the BCM. Not the two connectors that plug into the BCM, but the inline connector in the harness below it. Doing that dramatically changed the remote range from only working right outside the driver door glass to working from three houses down the street, and it's been working like that for a few months now where everything I tried before would only make a difference for days or weeks.

 

I cleaned the connector you (NMH3) referenced above...just to cross another action item off the list. I was praying for a miracle but nothing changed. I wish the issue was the antenna but everything there seems to be in good condition. A couple months ago I was even able to lock/unlock without the antenna connected as long as I held the FOBS near the BCM. I can't even do that now so I don't believe a longer antenna will make any difference. Does anyone believe the FOB/BCM lost programming and having them reprogrammed would make any difference?

As far as aftermarket remote start systems, what would be some recommended brands which play nice with the H3 electronics? I've read the H3s can be a bit fickle when it comes to those systems. I've never looked at remote start systems so any input/advice would be welcome.

 

Sorry that didn't work for you. For me, when I opened up that connector I could see corrosion on the pins and internal connector face and was thrilled that everything started to work again after I cleaned it with CRC.

If that hadn't of worked for me, my next step was going to be to find and clean the "G320" BCM ground connection under the rear of the middle console carpet. Not sure exactly where it is, but that's how its referenced on the wiring diagram. It seems to be the only ground dedicated to the BCM itself, vs. an input to the BCM from a related system. That ground stud is also associated with the two right doors and the tail gate door ajar switch, so if those ever don't work properly I would definitely dig into that more. The BCM antenna is certainly going to be more sensitive to a poor ground than a door open switch.

 

So for a status update. Had both key FOBS checked and they are transmitting just fine. Looked at pricing for an aftermarket remote start and installation. It's a bit cost prohibitive right now.

As a result, I ordered a refurbished BCM from GM for $200 that will fit our 06. I have read some owners send them off to have a 3rd party "clone" them. I don't like the idea of sending off our existing BCM for cloning because the vehicle is now dead until it returns. Also, I cringe at the thought of it being lost during shipping. So I'm looking at local/driveable 3rd party for this. I've also read people have taken them to the dealerships or a 3rd party shop to have them programmed. So I guess my questions is, should I have it cloned or should I have it programmed? Is there a difference? What are the pro's and con's for each?

 

So to give another status update...

Called around to 3 different dealerships for pricing and if they could reprogram the new BCM. Each one said yes and the pricing was about the same with the work taking a little over an hour. Had an appointment setup for Monday this week. About 2 hours in, the service tech comes over to me and says the data will only download so far until the BCM locks him out. They reached out to GM technical support Monday morning and received a response that afternoon with additional questions. Tuesday rolls around and they provide me with a status update, GM tech support is having them run through different steps. I receive a call this afternoon the vehicle is ready but the new BCM wouldn't accept any additional programming and they reinstalled the old one with no resolution at all AND no path forward. Their attitude was "sorry, we tried, you will just have to deal with it". They never could answer whether the BCM was bad (hard to believe since it came straight from GM) but I plan to return it. I VIN matched it to the vehicle and provided them with that documentation so they couldn't claim I was providing a junk yard part. I'm really at a loss at this point and looking to see what my next steps are. Should I even attempt an independent shop from GM? We have all of our vehicles serviced at a local shop because I feel they are more vested in providing good service but I went to a GM dealership since we are talking about VIN specific programming and it is a GM vehicle.

 

i had a similar proggraming issue with a chevy tailblazer it would never complete. it was a brand new GM pcm from the dealer. i had to bench program it out of the vehicle. something on the cars network was causing the programming to fail.