2007 Navigation Turning on/off Intermittently After New BCM?

[CAPT75]

So I’ve been battling with my 2007 Denali for over a year to get it running. First a bad PCV valve, then a bent intake valve causing loss of compression/misfire, machine shop fixed the head, bad starter, fuses, relays, etc...electrical gremlins. Probably due to the BCM going to sh*t, which I just replaced and resolved almost everything. It’s running now, still misfiring I think due to a clogged injector from the 18mo old gas that was in it(most is burned through now), but thanks to the BCM, it’s at least running. Problem is, after the new BCM, now the stock Nav unit is going haywire. Does the NAV unit run through the BCM? The truck starts, I see the GMC load up screen, and now it goes straight to the all blue clock screen. The volume/power knob is only sometimes responsive, and it’ll turn on to the Nav screen (or whatever it was on last), but after a few seconds it’ll go back to the blue clock screen and back to the Nav screen and flicker back and forth, sometimes for a split second, sometimes for 20-30 seconds, but it never just stays on. I’m not sure if my Denali had special order accessories since it has the Nav unit, but no backup camera, which I always thought was weird. So maybe it’s unique programming? But unless it runs through the BCM, I’d think nothing should’ve changed. I reached out to the shop I ordered the BCM from, and they programmed it to my VIN, and it has worked fine otherwise, but they haven’t heard of the issue before. Any other ideas besides an issue with the new BCM? Could the NAV unit have just crapped out after sitting so long?

 

[Doubeleive]

I would bet on the radio is just taking a crap, it would be extremely unlikely the bcm would make the radio do that, good excuse to upgrade!

 

[CAPT75]

Haha, that it is, but my main goal of getting the truck back up and running well was to trade/sell it for a new truck. Although being unemployed due to COVID sure makes that unlikely. So if I tracked down a compatible OE unit, does it need to be programmed to my VIN? Are newer OE units with more features compatible with an 07? Wouldn’t mind having Bluetooth to stream audio while I’m still using the truck.

 

[swathdiver]

So I’ve been battling with my 2007 Denali for over a year to get it running. First a bad PCV valve, then a bent intake valve causing loss of compression/misfire, machine shop fixed the head, bad starter, fuses, relays, etc...electrical gremlins. Probably due to the BCM going to sh*t, which I just replaced and resolved almost everything. It’s running now, still misfiring I think due to a clogged injector from the 18mo old gas that was in it(most is burned through now), but thanks to the BCM, it’s at least running. Problem is, after the new BCM, now the stock Nav unit is going haywire. Does the NAV unit run through the BCM? The truck starts, I see the GMC load up screen, and now it goes straight to the all blue clock screen. The volume/power knob is only sometimes responsive, and it’ll turn on to the Nav screen (or whatever it was on last), but after a few seconds it’ll go back to the blue clock screen and back to the Nav screen and flicker back and forth, sometimes for a split second, sometimes for 20-30 seconds, but it never just stays on. I’m not sure if my Denali had special order accessories since it has the Nav unit, but no backup camera, which I always thought was weird. So maybe it’s unique programming? But unless it runs through the BCM, I’d think nothing should’ve changed. I reached out to the shop I ordered the BCM from, and they programmed it to my VIN, and it has worked fine otherwise, but they haven’t heard of the issue before. Any other ideas besides an issue with the new BCM? Could the NAV unit have just crapped out after sitting so long?

When programming a BCM, even with a VIN, the technician has to know what options that vehicle has. If your Denali originally had the nav unit, it had the back up camera. It's possible someone added the nav unit, you'll have to decode your RPO sheet, identify your "U" codes.

 

[CAPT75]

So the BCM would have to be reprogrammed or the Nav unit would need to be reprogrammed?

 

[CAPT75]

Also, I have read that when people have upgraded to an OE Nav unit from another radio unit, the BCM had to be performances to recognize it or it would activate TheftLock. That’s not my problem though. It just turns on/off intermittently. It’s not locked. For the moments it stays on, I get sound, radio, aux, I can see the map, etc

 

[swathdiver]

So the BCM would have to be reprogrammed or the Nav unit would need to be reprogrammed?

Maybe both, there are sections for both. There is a website and a guy on Ebay who refurbishes these things. Worth a shot to contact them and let them know the symptoms you are having. Both have been reviewed by folks on here and they are great to work with.

 

[CAPT75]

What’s the name? I actually purchased the new bcm from an auto shop on eBay. You mentioned the RPO sheet and U codes. Is that something I can look into myself? Or only someone that has the equipment to program BCM’s?

 

[swathdiver]

What’s the name? I actually purchased the new bcm from an auto shop on eBay. You mentioned the RPO sheet and U codes. Is that something I can look into myself? Or only someone that has the equipment to program BCM’s?

The seller on ebay is OEMCARAUDIO, the RPO sheet tells us what your vehicle originally came with. Post up the "U" codes when you can.