Bcm

[Zues1355]

2010 gmc Yukon xl Denali-Hello having issues been at it for a month. Here are the issues I’ll give everything that transpired that let up to this whether it’s relevant or not.
this went on at the same time, truck was sputtering so I thought it was bad gas so I put in a can of system cleaner not sure of name brand it seem to help for about a week then I did it again
Next my front driver side headlamp casing gasket went which was allowed moisture to in the casing which led to the bulb going but passenger side still worked low and high beam
So I had to replace front hubs so decided to do all repairs at once. Truck sat for about a week. Replaced hubs , replaced both left and right headlights assembly, replaced fog light bulbs leds and low and head light bulbs leds.
Started truck dash lit up not recognizing the new hubs.
Also truck running rough. Discovered had a bad coil. Replaced all coils all pugs and wires. Which clears dash. Truck running smooth!
At night realized low beams now do not work but high beams and fog lights work.
Went through entire truck and checked all ground connections and tested all fuses and relays. By everything I research and was told Bcm was the issue.
So in short I bought the VXDIAG VCX Nano GDS2 and Tech2Win...and purchased the subscription off Acdelco.tds website.
I’m officially on my 3 Bcm low beams still don’t work now airbag light turn off. I used the programs recommended by acdelco recheck the fuses. The tech at acdelco let’s just saying it politely left hand doesn’t know what right hand is doing .
I NEED HELP!!!!!!!!!!!!!!!

 

[Fless]

Any DTCs, Pxxxx Bxxxx Uxxxx?

Are you saying that you replaced the headlights with LEDs? Is that when the headlight issues started? Low beam LEDs in backwards?

Have the low beam "bulbs" been verified to work, outside of the headlight fixture? Stranger things have happened....

The underhood fusebox shows a fuse for each of the low beams, as well as a relay. You could look up your vehicle at www.charm.li for a wiring diagram, as well as some diagnostic info.

I'm not sure why the BCM(s) would be condemned for this kind of light failure. Personally I'd revert back to the original BCM, but that's how I'd re-start.

And I wonder what kind of dash indicator showed for "not recognizing new hubs."

 

[Zues1355]

Any DTCs, Pxxxx Bxxxx Uxxxx?

Are you saying that you replaced the headlights with LEDs? Is that when the headlight issues started? Low beam LEDs in backwards?

Have the low beam "bulbs" been verified to work, outside of the headlight fixture? Stranger things have happened....

The underhood fusebox shows a fuse for each of the low beams, as well as a relay. You could look up your vehicle at www.charm.li for a wiring diagram, as well as some diagnostic info.

I'm not sure why the BCM(s) would be condemned for this kind of light failure. Personally I'd revert back to the original BCM, but that's how I'd re-start.

And I wonder what kind of dash indicator showed for "not recognizing new hubs."

Yes I replaced halogens with led but the bulb had went out prior to that due to gasket leak in right headlight assembly. Low beams still worked intil I parked the truck then the bs began , no dash light indicator showed up for the bulbs only thing indicator light was airbag and that didn’t show up until after we programmed Bcm, and now we can’t that cleared and low beams are still void. The indicator light showed for hubs was traction control but that cleared. The original Bcm was swapped as a core, I am on 3rd Bcm .

 

[j91z28d1]

how are you flashing bcm's?

using the acdelco website?

 

[Zues1355]

Yes I’m using the acdelco website and purchase the subscription and using

VXDIAG VCX Nano GDS2 and Tech2Win Diagnostic Tool Compatible for GM/OPEL with Global Diagnostic Programming System GDS & GDS2​

 

[mikez71]

does jumpering the relay turn on headlights?

check relay socket trigger ground. (grounds with light switch on, from bcm)
check relay socket supply voltage & trigger voltage. (always hot)

 

[swathdiver]

Put stock bulbs back in and the original BCM, clear everything and see what comes back after a full scan of all modules. There ought to be codes.

None of what's been done is the proper way to diagnose these problems.

The troubleshooting guide in the shop manual is your best friend.

 

[j91z28d1]

Yes I’m using the acdelco website and purchase the subscription and using

VXDIAG VCX Nano GDS2 and Tech2Win Diagnostic Tool Compatible for GM/OPEL with Global Diagnostic Programming System GDS & GDS2​

huh. my understanding was if it's the correct part number modual and it's flashed thru gm. the software is based off the options the vin number originally came with.

that's not good that other things unrelated didn't work right afterwards.