Jump to content

Daytime Running Lights not working

jeb
 Share

Recommended Posts

txab Senior Enthusiast

txab

Posted
Posted (edited)

DAYTIME RUNNING LAMPS (DRL)

The daytime running lamps (DRL) will operate when the ignition switch is in the RUN position, for automatic transmissions (A/T), the gear selector is not in the PARK position, the headlamp switch is in the AUTO position, and for manual transmissions (M/T), the park brake is released. 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 headlamps switch to manual control. 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-amp 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 , the DRL receive voltage on the DRL supply voltage circuit. Ground for the DRL is at G100.

 

 

 

 

 

2004DRLschem1.gif

Edited by txab
jeb Enthusiast

jeb

Posted
  • Author
Posted

Thanks. I'll find some time to see if I can trace it back. Looks like the BCM relay might need a look. But you'd think that since the DRL's do work for the lock/unlock, that'd be okay, too.

tesnoboy Enthusiast

tesnoboy

Posted
Posted

Did you buy this truck used? It sounds like somebody monkeyed up the DRL circuit. They should not be acting that way.

jeb Enthusiast

jeb

Posted
  • Author
Posted

Nope. As I said above, I bought it brand new. Been a great truck.

  • Like 1
  • 1 year later...
Gmcgeorge New Member

Gmcgeorge

Posted
Posted

I have a 2008 gmc sierra 1500 and I am the second owner. I just bought the truck and recently noticed that the driver side DRL light won't come on, but the passenger side does. Like you said about them flashing when you lock/unlock the doors, mine does the same, they flash but but when I turn the one won't stay on? I am totally confused about what is happening. I have been through it a million times and will take it in, maybe someone else can figure out what I can't!

Gmcgeorge New Member

Gmcgeorge

Posted
Posted

I found out it was just a fuse under the hood that I didn't check #26 (Driver Side Park Lamps) also the (passenger side park lamps) in your case is #27 if you haven't checked those under the hood that could be it!!

Gmcgeorge New Member

Gmcgeorge

Posted
Posted

I found out it was just a fuse under the hood that I didn't check #26 (Driver Side Park Lamps) also the (passenger side park lamps) in your case is #27 if you haven't checked those under the hood that could be it!!

  • 1 year later...
davester Senior Enthusiast

davester

Posted
Posted

Thx for listing the conditions the DRL's are on for, as I was incorrectly assuming they would be on with the engine [and was checking with it in Park, so no power to either plug, but fuse and relay were good, so I was about try digging into the wiring harness]. Thankfully, I googled for DRLs not working and came across this thread.

 

Now, I put on the parking brake, put it in gear, and like magic, power to the DRLs. One DRL was working fine, and the other has an iffy socket [there seems to be a bunch of burnt resin in the socket and both sockets and blubs look like they've been getting too hot]. I might have to go to the men's mall and get some replacement sockets, but it seems like they weren't designed right [as the bulbs should be able to be on all day without overheating the socket].

  • 3 years later...
Ccarpenter New Member

Ccarpenter

Posted
Posted

Jeb,  sorry I know this post was forever ago, but I have an 06 Silverado that’s doing the exact same thing. DRL‘s flash and stay on for 10 Sec when I’m unlocking the door just like yours, but they don’t ever come on during the day like they are supposed to. The fuses aren’t bad, and I’ve tries putting it in gear to make sure, did you ever figure anything out with yours? 

txab Senior Enthusiast

txab

Posted
Posted (edited)

Did you read completely through the posts and look at all the things mentioned?

 

First thing is to make sure your headlights aren't illuminated during the day

Edited by txab
Ccarpenter New Member

Ccarpenter

Posted
Posted

I did, headlights function normally, DRL’s come on when locking or unlocking doors and stay lit for around 10 seconds, otherwise I can’t ever get them to come on. Tried placing the truck in drive in the daylight, and checked the fuses.  

  • 8 months later...
Matt leggett New Member

Matt leggett

Posted
Posted

I have a 04 chevy 5.3l and have the exact same issue, they drl comes on for a delayed 10 secs when unlocking but wont come on when i have the key to on but engine off and parking brake on, head lamps work perfectly fine but the drls wont come on when driving...any suggestions

 

  • 3 years later...
Steve Griffith New Member

Steve Griffith

Posted
Posted

I had them when working but now the drivers side doesnt work. I checked the voltage coming out and it's only 2.0 volts. That's up?

davester Senior Enthusiast

davester

Posted
Posted

Well, you need to go back through the circuit and see where the voltage drop is.  The bulb connectors are known to have problems, as the original ones are just barely good enough to not immediately burn up.  Could also be corrosion, or a poor connection elsewhere.  You might also check that the ground connection is good.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Latest Articles

  • Posts

    • KARNUT
      OCI, not when but why?

      By KARNUT · Posted

      I see where you’re going and I can appreciate that. Statistics can be misleading because of the word average. They say statistics show the average cost of a new vehicle is about 50k. The average monthly payment is close to 1000 dollars a month. That’s statistics for you. I know very few people who pay that. 
    • silveradosid
      Replacing 2.7L on 2021 Silverado with 2023 2.7L

      By silveradosid · Posted

      same here , i have a 2020 first gen and the cost to repair these engines far excedes replacement
    • KARNUT
      OCI, not when but why?

      By KARNUT · Posted

      But Grumpy I did show several subdivisions that had homes starting in the 170K range. If you bought a Townhouse or Condo you could go cheaper. Same with a car 3000 dollars in the 70s translates to around 20K today. There are several models at that price. You actually get more for the money. In the 70s I drove a 3000$ car bought a 28K home and made 4.50 per hour. Thank goodness for overtime. Today I could buy a 170K house drive a 20K car and make 25 dollars an hour operating the same machine today. The difference the house, car, machine would be better and have AC. And I wouldn’t be taxed on overtime. And statistically your wife works too. Easing the burden. I thought we agreed to disagree. I brought receipts earlier, showing examples. I think you’re more stubborn than me. I was done with this debate. 
    • Coastie05
      Replacing 2.7L on 2021 Silverado with 2023 2.7L

      By Coastie05 · Posted

      I’m definitely interested to hear the end result here. 
    • MASONV88888888
      Another 6.2L engine failure!

      By MASONV88888888 · Posted

      My 2025 Silverado 1500 had to receive a brand-new engine (long block) under warranty last month at only around 16,500 miles. Before the replacement, the truck repeatedly displayed "Engine Oil Level Low" warnings, even though the Oil Life Monitor still showed around 50% remaining after about 6,000 miles since my last oil change. After seeing the warning several times, I checked the dipstick with the engine cold, and the oil level was completely normal. The next day, the message escalated to "Add Engine Oil." At first, I assumed it was just a faulty oil level sensor, so I brought the truck to the dealership. After inspecting the engine, they found internal cylinder wall scoring and ultimately replaced the entire long block under warranty. Before this happened, I was planning to install a 4-inch lift and suspension upgrade on my truck. After needing a new engine at just 16,500 miles, I honestly don't see the point anymore. I also contacted GM to ask whether my vehicle qualified for a buyback, but I was informed that it does not at this time. Anyway, this experience has left me with serious concerns about the long-term reliability of this engine. I sincerely hope NHTSA expands the current investigation or recall to include 2025 model and performs a thorough inspection of affected vehicles. My biggest concern is that these engines may fail shortly after the powertrain warranty expires. If GM truly stands behind this engine, then at the very least, please consider extending the powertrain warranty to 10 years for affected owners. That would go a long way toward restoring customer confidence.

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...