My point is to simply send 12v direct(bypass everything)
1- lights work, then backtrack.
2- lights still don't work, check bulbs/connectors/wiring/ground to the bulbs.

 

my hands are still defrosting from checking.
the drl turn on when relay is closed manually. so now i have to backtrace the relay coil ground to the bcm check at c2/b4 in your diagram or re install the old flasher relay module and see it that some how sends a signal to the bcm to trigger the drl's or is part of the c2/b4 circuit.
i guess i can also check with the tech 2 if i can interface with the bcm and control the drl with it.
might one of you guys have a schematic for the flasher module relay pinouts? i dont think i saw them in oceanbraves pdf but maybe i am not looking at it correctly. the module goes plugged into the back of the drivers dash side fuse panel

 

Great, the drl's work. Back to your conspiracy theory.

 

Don't forget to check/clean contacts here:

 

The only way to make the comically gigantic daytime running lights work with a Tahoe fog light button is to add additional relays. The stock wiring to those are for DRL only. There has never been an H2 that came from the factory with those as driving/fog lights. I did a pretty extensive writeup on what is involved in making them actual fog lights along with wiring info needed to make the Tahoe fog light momentary button work. There is a possibility of doing it through the BCM but you would need a BCM from a Tahoe and I'm not sure what the implications of that would be as it would affect the stereo system and climate control as well and likely would cause other systems to stop working right..

Read this thread if you want to make a Tahoe fog light button work in an H2... https://www.hummerforums.com/forum/h...-lights-39090/

 

ok bench tested the old flasher module with the above diagram i cant see where it would affect DRL's so i guess i have other issues to track down. or just do the diode mod to something that runs when on. like fuel pump relay back feed the negative of the coil should give me the benefit of working as long as the truck is running and on a plus runs when headlights are on. they are led so should in theory have a long life span compared to running the factory halogen DRL's all the time.
can the E-brake turn the DRL's off? i do use it daily but the dash light for the e-brake works fine on the cluster. on when pressed and off when disengaged. does the E-brake have a double function type switch?

 

thanx mixman i had Read your thread. my issue does not have to do with that other than i have a taho switch on my truck.
my issue is DRL's stopped working normally. but if i manually trigger the drl relay it works. so that means bcm not telling it to turn on. i have not had any bcm issues before noticing this recent development. i thought maybe the flasher relay had to do with the issue as it was the last thing installed on the h2.
maybe i just need to remove the truck battery and reboot lol

 

Thanks for asking.

Still in progress, spoke to AJ, he's gonna take a look at it. Keep you posted.

 

Ah - in that case it then the the DRL relay and fuse are fine if you can trigger them on with the Tech2. Only other thing I can think might be the ambient light sensor on the top of the dash. That is what triggers the headlights to turn on and I'd assume is what also triggers the DRL's to turn on. One other thing that can prevent them from coming on is the parkign brake. Below from the GM eSI.... Attached is the troubleshooting doc.

"Daytime Running Lamps (DRL)
The DRL will operate when the ignition switch is in the RUN position, the gear selector is not in the PARK position, and the headlamp switch is in the AUTO position. When these conditions have been met and the ambient light sensor indicates daytime conditions, the DRL will illuminate. The ambient light sensor is a light sensitive transistor that varies its voltage signal to the body control module (BCM) in response to changes to the outside (ambient) light level. When the BCM receives this signal it will either turn on the DRL or the headlamps for auto headlamp operation. Any function or condition that turns on the headlights will cancel the daytime running lamps operation. The DRL can be manually turned OFF by depressing the AHL/DRL switch in the headlamp switch. The AHL/DRL defeat switch sends a ground signal through the DRL switch signal circuit to the BCM. The BCM then turns OFF the DRL and turns ON the DRL OFF lamp in the headlamp switch by grounding the DRL OFF indicator control circuit. When the AHL/DRL are manually turned OFF at the headlamp switch, the AHL/DRL will default to ON with the next ignition cycle. The DRL are separate lamps independent of the headlamps. With the headlight switch in the AUTO position, the DRL will either be turned ON or OFF, after an approximate 8 second delay depending on whether daylight or low light conditions are sensed.The DRL 10 A fuse in the underhood fuse block supplies battery positive voltage to the DRL relay switch contacts and relay coil. When the BCM energizes the DRL relay on the DRL relay control circuit in daylight conditions, the DRL receive voltage on the DRL supply voltage circuit. Ground for the DRL is at G100."

 

yeah my last guess would be the E-Brake. as the twilight sensor works as it should. the DRL's run if i jump the relay coil to ground. but my e-brake seems to also work fine. step on it dash brake warming illuminates. disengage it warning shuts off. so unless the E-Brake has more then one switch i dont know where else to go.

what you posted above seems different then how my truck used to function though.
in auto mode the minute i would turn the truck on even in park my DRL's where on until it got dark enough to trigger the headlights to fire.

does a hummer even have this " AHL/DRL defeat switch "
i dont see one on the switch other then the O