DRL not working / All fuses, relays and bulbs good

[Inspignant]

Just noticed that I had no DRL's when I went to do the mod for the Headlight and DRL both on mod. I have checked both bulbs, good. DRL fuse, good. Relay, good. Light sensor in dash, good. I understand that for the DRL's to work you need to have the engine on and in Drive. What else could I be missing? Last year I installed Xenon HID headlilghts but my DRL's were functioning.

[fyr145]

double check your mod connections between each relay. You also may have the wire in the wrong direction as the mod requires the use of a diode.

the final issue could be the HID's may not allow this type of mod.

[Inspignant]

I will check the HID relays that come with the kit. I need to mention that the DRL's used to work when I first installed the HID's. I also have not done the mod yet for the DRL and Headlights on at the same time yet since I noticed the problem with the DRL's not working anymore.

New DRL bulbs
New DRL relay installed correctly
New Fuse
Working Light sensor (checked with flashlight at night) Headlights go off but DRL's dont come on.

[LoJac963]

The HID's should be wired completely separate from the DRL's and should have nothing to do with them not working.

As FYR said double check your wire and diode that it's in the right direction for the DRL mod. That honestly is the only thing that has changed and they no longer work.

[Inspignant]

Thanks guys, I will be digging into this, this weekend. Seems I am having more issues now. The Cruise control is not working now, and it worked last week. Will update with findings. Thanks again.

[glennf1]

I just did this mod too and the same thing happened. I metered it and there is no longer voltage coming from the BCM. Apparantly, the voltage going backwards to the BCM from doing the mod fries the transistor that switches it. Now I just have the DRL on with the headlights. I'll just live with it instead of buying another BCM module. Others have gone years with no problems.

[LoJac963]

Oh **** I hope that's not what happens when you install it backyards!!

Hope you guys get this worked out. Keep us updated!

[Inspignant]

Im sure installing it backwards could probably fry something but I am positive that is not the case. I do however think that the Anti flicker capacitor that is installed in the HID system could be the reason that the DRL's are not working. I have emailed the company and hope to hear back from them soon.

Spending over 90 hours a week working on private jets is all fun and games but do I really want to go home and spend more time troublshooting an electrical problem when I could come here and possibly get lucky and find the answer to my problem.

(As he says in a sarcastic tone and quoting a line from THE MASK)

I'd like to think so, Haa Haa

[Inspignant]

And yes, I will keep you posted.

[Inspignant]

So I took it to the dealer and they were not able to find the problem and they used to be a hummer dealer, WTF. They tested the BCM and it was fine. So Last night I put everything back to OEM because I had a bad ballast for one of the HID's and the DRL's still do not come on. Im at the point now that if when I check the relay and fuse tonight, if they are good, then I am wiring it straight in with the headlights. Stick a fork in it, I'm tired of jacking with it.

[LoJac963]

You even removed the DRL mod diode and they still didn't work?

[HUMTECH]

Does the DRL relay turn on? Check for power at pin 86 of drl relay when in drive, engine running(with help of a second person) don't want it to drive away on you. Check for ground signal at pin 85 from BCM. Check for power at pin 30. If you have all those problem is from pin 87 to lamps or bad ground tp DRL lamps. I would suspect open in underhood fuse block from pin 87 to connector c4 pin b2 dark blue wire due to modification done over loading circuit.

[Inspignant]

yes, I removed the Diode and still no lights. I will try your suggestion for checking ground and power. Stay tuned.

[KTM640Dakar]

Check the harness connections that plug into the bulbs. They usually need dielectric grease put on the contacts. If your cruse control stops working it is a sign of a burnt out DRL bulb.

[HUMTECH]

Um the DRL's have nothing to do with cruise control, brake lamps and high mount brake lamp yes but DRL's, nope

[baldfox]

Did you manage to find a solution ? My DRLs are as dead as a dodo. I thought initially the bulbs had gone (i bought the h2 like that) but having tried to replace still nothing. I checked the fuse too (2008 - no.26- but it looks ok).Am stumped too ?!?!

[KTM640Dakar]

The bulb holder in the DRL which is L shaped and connects into the harness is probably bad. I had one go bad on me. You can disconnect the holder from the harness via the quick disconnect and use a multimeter to see if you have continuity between the pin and the bulb holder contact. For some reason they break internally and you have to replace the holder.

And yes if you lose a bulb or lose connection in the DRL the cruise control will not work. Not sure why GM does that but all my Chevys lose Cruise control when a bulb is out.

[HUMTECH]

If you say so, ive been working on GM vehicles for 17 years and owned them much longer than that. Not once has my cruise been disabled due to a in-op drl lamp. So I guess US spec trucks with drl defeat or simply not equipped with drl's don't come with cruise?