Headlights Turn On in Drive, Off in Park

[tkdgirl]

Weird issue. With the headlights set to auto, my headlights are ALWAYS on when driving (no, not my DRLs). In park, they are off, but in Drive, they come on. I replaced the light sensor but no luck. Reseated the relay an nothing. Any other ideas?

2011 Yukon XL Denali

 

[gooffeyguy]

Normal

Yukons use the low beam headlights as the daytime running lights.

Directly from my 2012 owners manual

 

[blondie70]

Can one pull a fuse to disable the DRL's ?

 

[Geotrash]

Weird issue. With the headlights set to auto, my headlights are ALWAYS on when driving (no, not my DRLs). In park, they are off, but in Drive, they come on. I replaced the light sensor but no luck. Reseated the relay a nothing. Any other ideas?

2011 Yukon XL Denali

Are your taillights on during daylight in drive also?

 

[Doubeleive]

Weird issue. With the headlights set to auto, my headlights are ALWAYS on when driving (no, not my DRLs). In park, they are off, but in Drive, they come on. I replaced the light sensor but no luck. Reseated the relay an nothing. Any other ideas?

2011 Yukon XL Denali

headlights on the yukon are multi-function
they perform drl, low beam, high beam all in (1) bulb
it is hard to tell the difference between drl & low beam but in drl mode the voltage is slightly lower and therefore a tiny bit dimmer than low beam mode.
you can turn drl function off by flipping the light switch to off with the key on, as soon as the key is cycled you would have to peform the same function again in order to keep drl off.
to bypass that you would need to remove the spring from the switch or pull the drl fuse.

to elaborate a little more drl function happens when the vehicle is put in drive
the drl function is disabled if the parking brake is applied
the drl function is disabled at dusk when the sun sensor flips the relay over to low beam mode and applys the full 12v
the drl function is enabled at dawn when the sun sensor flips the relay to low voltage drl mode, I believe it is 10~11v

 

[tkdgirl]

headlights on the yukon are multi-function
they perform drl, low beam, high beam all in (1) bulb
it is hard to tell the difference between drl & low beam but in drl mode the voltage is slightly lower and therefore a tiny bit dimmer than low beam mode.
you can turn drl function off by flipping the light switch to off with the key on, as soon as the key is cycled you would have to peform the same function again in order to keep drl off.
to bypass that you would need to remove the spring from the switch or pull the drl fuse.

to elaborate a little more drl function happens when the vehicle is put in drive
the drl function is disabled if the parking brake is applied
the drl function is disabled at dusk when the sun sensor flips the relay over to low beam mode and applys the full 12v
the drl function is enabled at dawn when the sun sensor flips the relay to low voltage drl mode, I believe it is 10~11v

Thank you for the explanation. Appreciate it.

 

[tkdgirl]

Are your taillights on during daylight in drive also?

Good question. Will check in the morning.

 

[Doubeleive]

Good question. Will check in the morning.

the only way you will be able to tell is with a helper or look in a reflection in glass or a mirror behind you with brakes off.
you could block the front wheels and put it in drive, then get out and look.
while the wheels are blocked or brakes applied and in drive you could cover the sun sensor with a jacket or something and a few seconds later you should here the relay click and low beams will switch on.

 

[petethepug]

Good Q by @tkdgirl. The most obvious one I took for granted. The Yukon and it’s headlamps that are about 10 years behind in their technology.

The initial reaction I had was to throw BT Dieselworks tune & autosync out there. It turns off the DRL / daytime running lights. When I googled DRL BT Dieselworks, this came up …

Flashing a BCM via Autocal and BT Dieselworks

I just completed this and thought I’d share my experience so that others can learn and understand how this works. First I want to say that I did initially encounter a difficulty with obtaining my BCM tune and I did send a follow-up email to the initial order confirmation, followed a few weeks...

www.tahoeyukonforum.com

A damn fine read on the other half of the BTdiesel functionality for the 07-14 I wasn’t aware of. It also shows the venerability of a business owner who runs his shop as a one man show.

I’ve really got to thank that guy for taking his love of the 07-14 & 15-20 full size GM SUV & Trucks to the next level. In spite of doing the job that 10-15 people should be doing, he’s found a way to keep his business proprietary and share it with other owners to enjoy.

 

[tkdgirl]

Are your taillights on during daylight in drive also?

Nope