I am having a problem with my 2008 Hummer H3 keyless entry remote

The remote door entry is intermittent I also was experiencing TPM codes. Last year after crimping and re-routed the existing BCM Antenna, the problem was resolved, however the same problem (not working, intermittent, short range) has resurfaced. My recent attempt to crimp the antenna connector (to make a tighter fit), and again re-route the antenna to protrude up through the passenger dash molding, has had limited success. This time I removed the proprietary (plastic) retaining clip from the antenna wire and attached it directly to the post on the BCM PC board. I thought a more direct fit would help, (Eh?). After testing, the key fob, the transmitter has limited range; its battery strength is also 3.24 volts. I have searched the internet for a replacement antenna (Part # 25792116) to no avail (always Out of Stock or Discontinued). I found another antenna online (Part # Antenna Assembly - R/CON Door Locking RCVR) Part Number: 25845987 Supersession(s): 25845987; 15850014) for a 2007 Monte Carlo that looks the same and I was wondering if it will work? But, is this problem more likely a malfunction in the programming (requiring a Dealer Flash) or is it possibly a BCM hardware problem? I saw there was a GM Bulletin posted somewhere that mentioned something like this? Obviously I don’t want to spend a lot of money at the Dealer if I don’t have to, so any help would be most appreciated. Thank you.

 

Welcome Martin, I MOVED this for you to the H3 section where ALL H3 Tech Questions go.

Do you have a sunroof? If so, has your passenger side floor ever been wet? If so, that may have damaged the BCM, or instilled corrosion and compromise to it and its harness.

IMHO you are chasing the OEM fob function down a Rabbit Hole. You could buy a replacement BCM/reprogram it or try the one you have. Pull the BCM and clean the board and play with another antenna, etc... and still get nowhere.

Better off installing an Aftermarket remote entry & start that all have far better range than the OEM fobs ever did and the added feature of remote start.

 

I went down the sunroof rabbit hole years back. Followed all the tips I found - still had a leak. It was only after I had to replace the windshield wiper motor that I discovered the actual source of my leak. One of the proprietary plastic clips that holds the plastic molding in place (above the wiper motor components, linkage etc.) had a dry-rotted rubber seal. The hole it fits in is located directly above the glove box. I replaced it and sealed it as a precaution with silicone (problem solved). Regardless, I removed the BCM, checked and cleaned the connections including the PCB, visually nothing looked corroded. Still as you say - can be the problem. I've always shied away from remote starts and I'm unfamiliar with how they work / install. How would this help my problem? Does it eliminate the existing key fob(s) altogether? Can you recommend one? Thanks Doc.







QUOTE=Doc Olds;406059]Welcome Martin, I MOVED this for you to the H3 section where ALL H3 Tech Questions go.

Do you have a sunroof? If so, has your passenger side floor ever been wet? If so, that may have damaged the BCM, or instilled corrosion and compromise to it and its harness.

IMHO you are chasing the OEM fob function down a Rabbit Hole. You could buy a replacement BCM/reprogram it or try the one you have. Pull the BCM and clean the board and play with another antenna, etc... and still get nowhere.

Better off installing an Aftermarket remote entry & start that all have far better range than the OEM fobs ever did and the added feature of remote start.[/QUOTE]

 

How would it apply? I have seen people on here over time invest more and more cabbage in trying to get the not so great OEM type fobs to work and still have issues.

You would stop wasting time & $ chasing that rabbit = OEM fobs that had a short range and only unlock/lock the doors. Throw those out and use the new fobs that come with your new remote start/entry system that has its own antenna, 2-3Xs the range, and is all NEW. Problem solved for a known amount of $ (you pick whatever brand and installer you want) with the added feature.

Kinda like spending money on 16 year old washer or dryer vs buying new....

Good luck.

 

I am having the same trouble. I did find a new antenna and installed it. Nothing. It won't go into program mode either for the key bob. Do I condemn the BCM? and if so. how will I get my TPM to work with an after market keyless entry. any help is appreciated.

 

Doc's right. I had a Clifford remote start/door unlock installed 12 years ago and never had a problem. I've tested it's range and have easily gotten a block away or more.

 

An aftermarket alarm with remote start does NOT replace your BCM, it is an add on. Your BCM is untouched and will not be disturbed so if it works with your TPMS, it will still be there doing that.

 

Thank you. I appreciate your reply. I will add an aftermarket. I still don't understand why it wont go into relearn mode for tpm's or Program mode for key fobs. I did the process exactly and neither responded. But my relearn on my engine works.

 

Hi again. I'm still struggling with the lack of communication between key fob and BCM. I ordered a "Used BCM" from eBay and have yet to have it "Flashed" by the dealer (next week). In the interim I opened my original BCM and inspected the circuit board. I found a section that seemed either corroded or burnt (see pic). I took a fine needle to clean around the area - lightly scraping the corrosion off and then cleaning that area with electronic lubricant/cleaner. Because I have no schematic, I have no idea what this section on the board pertains to in the BCM's functions. I also checked on the "Used eBay" BCM (un-flashed) that I bought and found a similar but not as obvious burn/brown mark on the top of the same component (see Pics). I tested for "continuity" but am not ever sure if this component should have continuity (which it did). I re-installed the BCM, but had no luck in creating a com link with the fobs. However, a new problem surfaced. After shutting the engine off with the key and manually locking the doors, within minutes the horn starts pulsing. Then the only way to stop it is to put the key back in the ignition and start it up again. But as soon as I shut it off and close / lock the door, within a few minutes the horn alarm goes back on. Once the the engine is running, the vehicle operates / runs fine. It's only when the engine is off and the key removed that the horn starts cycling again. Since the start of this problem, I've noticed a distinct smell of (as my brother says) wires burning within the driver's compartment. There's never any smoke, and I'm fairly certain it's not coming from the BCM. So what might I be overlooking behind the dash that's related to "fob-com - horn-alert" and could be causing this smell? Something within the Ignition circuit? On Star? or the radio? What else is back there? Thanks!
This is my Original BCM circuit board. The component at the top and o its right are questionable.

This is the eBay "used" BCM yet to be "flashed" at the dealer. Again, the component in question is top-right. Maybe this is normal?

 

I had similar problems. I found a new oem Antenna instaleed it with no effect. My tps was not going into relearn mode along with no Key fob programing. When a brand new antenna did not work. I was going to condemn my BCM.. I thought i needed it for other features. So I decided to put in an aftermarket keyless entry & remote start. When I got it back from the install. Everything was working again except the oem key fob. which is ok. The aftermarket works so much better. No tpm light either and it goes into learn mode. So keeping my fingers crossed. very Happy now.