About two months ago I got water leaking down the passenger side A pillar from the sunroof of my 2009 H3T Alpha. It apparently got into the BCM and suddenly my key fob only worked if I held it right next to the passenger door., although everything else the BCM controls was fine. So I took it to the dealer I bought it from in 2008. We'll just call them Acme Motors - that's not their real name. (Their real name is Valley Cadillac). They had it for a week and finally informed me I needed a new BCM, part no. 20987862 but that part was discontinued by GM and they couldn't find a new one but if I could find a used one they would put it in for me.

So I went to the local junkyard and they found me a 20987863 which they swore the computer said was a cross for the -62 and that it would work. I bought it and took it over to Acme. Another week later the6y called to tell me that module was no good and the truck wouldn't even start with it in, so they put the original BCM back in. So I went on Ebay and found a correct matching used -62 part number. Another week later it arrived and I took it over to Acme. After still another week they called to say this module was also no good. They said you couldn't put a used BCM in the Hummer because the VIN is hard-coded in the module and can't be changed and that's what it didn't work (which I believe to be a bunch of baloney).

So they put the original BCM back in and apparently having tired of me told me to come by and pick up the truck. When I got home I took a look at the odometer. It was reading 29,972 when I took it in. Now it's reading 174,793! And it's not rolling, so it's stuck on that number. And now the trip counter also doesn't work. It's stuck on zero. And it says I need an oil change, which I don't.

So I called up Acme to complain. Their response might be summarized as "Duh?". Does anyone have any advice on what to do from here? I love this truck and it still performs great. But having an odometer reading that's suddenly over 100,000 miles too high is unacceptable. And the key fob still doesn't work either. :-(

 

Welcome.

Never ever, under any circumstances take any used vehicle out of warranty to a dealer. They overcharge for underwhelming capabilities. Most of the young techs there now likely never worked on any Hummer.

First, do the sunroof drain fix so this will not happen again.

Knowledge is power, get some by reading about H3/H3T BCM replacement. There are some threads here and on the web. Yes you can swap in a used BCM and it can be programmed with a Tech II or equivalent tool by an actual technician that knows what they are doing, but.... The odometer gets the miles to display from the BCM storage. So you odometer will be at whatever the donor truck had on it. That is where the new one comes in.

Did you get your parts back from them? They did not put your original BCM back in and you know that because the miles are displayed from a replacement. You can buy a BCM and have it programed to your vehicle by mail order as well (nut shell: you send your old bad BCM and they copy it over - clone it - to the replacement). There is a pretty recent thread on how to clean the BCM and tweak the antenna for better OEM Fob function.

If you would have asked at the stage of "my OEM FOB doesn't work" I would have told you stop messing with antiquated garbage and get an aftermarket alarm/remote start installed for far greater range and added function, then toss the OEM Fobs.

Good luck.

 

Ah yes, I guess everybody has 20/20 hindsight :-) I should have discovered this forum years ago. The idea that they put the wrong BCM back in was good, only they didn't. I checked the serial number of the used one I bought and it matches the part they gave back to me, so the one in the truck now is the original BCM.

Why I went to Acme is a long story. I contacted three independent reapir shops here and no one wanted anything to do with this. Apparently "Hummer BCM" is a synonym for "anthrax" . I contacted a Chevy dealer since the Hummer is based on the Chevy Colorado. They said no. A second Chevy dealer said take it bak to where you bought it. So not having either a shop manual or a Tech 2, it was back to Acme. Anyway, they're close by and I have a long working relationship with them. But you're right - the original Hummer crew is long gone and the current crop of techs there is completely clueless.

I *really* wish I'd known about the key fob replacement idea. That would have solved everything right there since the rest of the original BCM was working fine. Oh well. And I also wasn't ware that stupid sun roof drain system had a fix.

So this is where we're at. After some discussion Acme has agreed to take it back in. Fortunately, they have an official record of its actual mileage taken direct from the OBD2 when I brought it in. They're going to send that, along with the original BCM and the used one I bought to Garrett Tuning in Ohio for cloning and odometer correction, and then put the cloned BCM back in the truck. Then *hopefully* everything will work again. But then again hope and a nickel will buy you a cup of coffee (it's a very old saying. We'll see...

 

i just posted this on another thread

 

Thanks for that video. If Garrett doesn't come through, we'll be talking.

 

in the video he states they would also need the cluster to correct the milage issue. they might have to also send that to garret.

 

Good catch - I'll mention that to them. They're not even going to get to it until Jan. 3.

 

Good luck with the issue and keep us posted.

 

Thanks. The funny thing is that the key fob actually still works - you just have to hold it very close to the front passenger door. I'm really not convinced there's anything seriously wrong with this BCM. I'll bet if you gave the board a good cleaning it would fix that problem. I'd do it myself but I'm afraid of screwing up something else in the process. Of course now with the odometer issue it's a different story. At least now it's Acme's problem, not mine.

 

Well this whole sorry situation is rapidly going from bad to worse. After putting me off for over a week for the holidays, I called Acme, oh the heck with it, I called Valley Cadillac yesterday morning. Dino, the service adviser didn't answer. I left a voicemail. Two hours later, no call back so I called the service manager. He didn't answer so I left another voicemail. No call back. So finally I just drove down there and cornered Dino. He informed me that Valley Cadillac was washing its hands of the whole deal and walking away. He refused to do any more work on the truck. This is how they left it:


H3T BCM extraction

H3T corrupted odometer
So now I don't know what to do. I suppose I could unplug the BCM and send it to Garrett for cloning with the new used one I got last month. But it appears the corrupted mileage has propagated to the instrument cluster due to Valley's incompetence. Do I need to send that off too? I have no idea how to do that. They need to correct it to the true mileage (30,277). Then I'll have to rent a car while Garrett patches everything up. Oh and the check engine light is still on, after they charged me $1200 to fix ("Replaced Evap Vent Solenoid") ARRRGH!