How do I permanently stop the AutoHeadlights from coming on at startup?
Junior Member
Joined: Apr 2019
Posts: 4
Actually you can not defeat it through the switch.
The ambient light sensor operates between two voltages. If the ambient light drops too much, the voltage changes and the BCM turns the headlights ON. Conversely, if the ambient light is high, again the voltage changes and turns (the already on headlights) OFF.
I have done my homework on this feature.
The only way you could control the headlights by disassembly of the headlight switch would be to have the lights never come on, ever.
Bottom line is just leave this feature alone and let the truck do its thing. Are you reading this Ski.dive ??
The ambient light sensor operates between two voltages. If the ambient light drops too much, the voltage changes and the BCM turns the headlights ON. Conversely, if the ambient light is high, again the voltage changes and turns (the already on headlights) OFF.
I have done my homework on this feature.
The only way you could control the headlights by disassembly of the headlight switch would be to have the lights never come on, ever.
Bottom line is just leave this feature alone and let the truck do its thing. Are you reading this Ski.dive ??
the sensor is located on the dash, must be pretty easy to disconnect. If the lights still come on, then we need to fin out what voltage it gives in daylight.
If the lights dont come onn if the sensor is diconnected, then you can even add a switch to disable automatic lights when you need to.
Then the daytime running lights might need disabling , so that all lights stay off.
To go full stealth mode lol, PM for tips hahha
Senior Member
Joined: Aug 2007
Posts: 997
From: Reno, NV
I'm afraid that your info and assumptions are incorrect.
The sensor controls the voltage and the BCM software program controls the lights (on/off).
If it were a simple turn on turn off by the sensor the lights would come on and off too rapidly.
It sounds like you have an idea to drive at night with no headlights, which is just
a ridiculous and dangerous idea
One further bit of proof of the headlights complicated operation is the wiring to the headlights.
There are only three wires to the headlight bulb 12V, high beam and low beam.
The DRL function is again controlled through the BCM, not through a separate wire
The sensor controls the voltage and the BCM software program controls the lights (on/off).
If it were a simple turn on turn off by the sensor the lights would come on and off too rapidly.
It sounds like you have an idea to drive at night with no headlights, which is just
a ridiculous and dangerous idea
One further bit of proof of the headlights complicated operation is the wiring to the headlights.
There are only three wires to the headlight bulb 12V, high beam and low beam.
The DRL function is again controlled through the BCM, not through a separate wire
Last edited by wfturner; Apr 14, 2019 at 05:33 PM.
Senior Member
Joined: Jul 2012
Posts: 9,016
From: C-Town
There is a way then,
the sensor is located on the dash, must be pretty easy to disconnect. If the lights still come on, then we need to fin out what voltage it gives in daylight.
If the lights dont come onn if the sensor is diconnected, then you can even add a switch to disable automatic lights when you need to.
Then the daytime running lights might need disabling , so that all lights stay off.
To go full stealth mode lol, PM for tips hahha
the sensor is located on the dash, must be pretty easy to disconnect. If the lights still come on, then we need to fin out what voltage it gives in daylight.
If the lights dont come onn if the sensor is diconnected, then you can even add a switch to disable automatic lights when you need to.
Then the daytime running lights might need disabling , so that all lights stay off.
To go full stealth mode lol, PM for tips hahha
Senior Member
Joined: Jul 2012
Posts: 9,016
From: C-Town
I'm afraid that your info and assumptions are incorrect.
The sensor controls the voltage and the BCM software program controls the lights (on/off).
If it were a simple turn on turn off by the sensor the lights would come on and off too rapidly.
It sounds like you have an idea to drive at night with no headlights, which is just
a ridiculous and dangerous idea
One further bit of proof of the headlights complicated operation is the wiring to the headlights.
There are only three wires to the headlight bulb 12V, high beam and low beam.
The DRL function is again controlled through the BCM, not through a separate wire
The sensor controls the voltage and the BCM software program controls the lights (on/off).
If it were a simple turn on turn off by the sensor the lights would come on and off too rapidly.
It sounds like you have an idea to drive at night with no headlights, which is just
a ridiculous and dangerous idea
One further bit of proof of the headlights complicated operation is the wiring to the headlights.
There are only three wires to the headlight bulb 12V, high beam and low beam.
The DRL function is again controlled through the BCM, not through a separate wire
Junior Member
Joined: Apr 2017
Posts: 18
I don't know why everyone is being a jerk about the guys question. He probably just wants to shut off the daytime running lights.
I can't stand cars running headlights during the day either. You can just pull out one of the fuses under the hood and it shuts the function off. Easy.
Found another thread about this a long time ago and it works. Let me see if I can find out which fuse it is. 4 years ago is too far back to remember.
I can't stand cars running headlights during the day either. You can just pull out one of the fuses under the hood and it shuts the function off. Easy.
Found another thread about this a long time ago and it works. Let me see if I can find out which fuse it is. 4 years ago is too far back to remember.
Senior Member
Joined: Aug 2007
Posts: 997
From: Reno, NV
What is the "LDR" ?
Senior Member
Joined: Aug 2007
Posts: 997
From: Reno, NV
I figured it might be that . . .
ski.dive-
And . . . the DRL function is not controlled by the ambient light sensor on the dash.
The DRL is solely controlled by the BCM. Pulling fuse #39 defeats just the DRL function, which is old news to most of us.
And installing a permanent resistor in place of the ambient light sensor could cause problems with the BCM.
Isn't it easier to just turn the headlight switch to the left and release after you start driving ?
ski.dive-
And . . . the DRL function is not controlled by the ambient light sensor on the dash.
The DRL is solely controlled by the BCM. Pulling fuse #39 defeats just the DRL function, which is old news to most of us.
And installing a permanent resistor in place of the ambient light sensor could cause problems with the BCM.
Isn't it easier to just turn the headlight switch to the left and release after you start driving ?
Last edited by wfturner; Apr 18, 2019 at 08:42 AM.
