'09 DRL or Auto Lights Disable?
01-24-2012 | 07:06 PM
#91
Senior Member
Joined: 12-24-2008
Posts: 717
From: N/A
Now the downside...
The voltage the BCM receives back, controls the odometer/DIC display as well as the factory radio display brilliance. This modification causes these displays to be at full brilliance day & night (you get used to it). The rheostat only controls back-lighting of the instrument panel and instruments. ...Thoughts...?
The voltage the BCM receives back, controls the odometer/DIC display as well as the factory radio display brilliance. This modification causes these displays to be at full brilliance day & night (you get used to it). The rheostat only controls back-lighting of the instrument panel and instruments. ...Thoughts...?
I currently have a 4.7K ohm resistor installed in parallel with the light sensor I am pretty happy with. On those few occasions the lights(interior and headlights) do not come on early enough, like when it is getting dark outside, I simply throw something on the dash sensor to make the BCM think it is dark outside.
I know nothing about HIDs. Nor do I want to – the HHR has the best headlights I have ever had on a vehicle. Now if I could only get my off-road Samurai to light the road this well.
Several questions:
Seems like you actually unplugged the connector from the light sensor and plugged in a Zener diode. How did you gain access to the connector way up under the dash?
What happens to the operation of the light sensor circuit if you leave this connector unplugged with nothing plugged into it, either a resistor or a diode? Otherwise - an open circuit. I may have discovered and since forgotten the answer to this question, it has been a long time since I was experimenting around with this circuit.
01-25-2012 | 12:49 AM
#92
Member
Joined: 09-27-2010
Posts: 38
From: Yulee, FL
Yes, I did actually unplug the connector, inserted the diode, secured the connector out of the way and left the sensor in the dash panel (and I have the scrapes & scratches to prove it). If I remember right, I took out my in dash glove box and possibly the instrument gages. I do remember trying to remove the panel as told by the shop manual on alldata, which included removing the passenger airbag cover, but I could not figure out how they wanted me to accomplish it. So, gaining access was a 'pain in the arm(s)' in trying to reach the sensor connector.
If you leave an open circuit at the sensor, the output voltage from the BCM is not received back at the BCM. So, with 0 voltage received, it thinks that its dark and the Auto Headlights come on.
As for the instrument panel back lights dimming separate from the vacuum fluorescent displays of the DIC and Radio... (from alldata)
If you leave an open circuit at the sensor, the output voltage from the BCM is not received back at the BCM. So, with 0 voltage received, it thinks that its dark and the Auto Headlights come on.
As for the instrument panel back lights dimming separate from the vacuum fluorescent displays of the DIC and Radio... (from alldata)
Radio Head Dimming
Dimming and backlighting levels are determined by the serial data messages the radio receives. (BCM)
All in all, your way is probably the best compromise at taming the Auto Headlights, rather then my method of disabling them in this manner.
Interior Lamps Dimming
When the ignition switch is turned to the ON position, the VF displays (radio) turn ON at maximum brightness. When the park lamps are ON and the ambient light sensor indicates low light conditions, all incandescent back lighting turns ON at the dimming level indicated by the instrument panel (I/P) dimmer switch. At the same time all VF displays dim to match the indicated dimming level. The body control module (BCM) is responsible for the dimming of the interior lights. The BCM receives a varying signal from the I/P dimmer switch. Based on the position of the I/P dimmer switch, the BCM then supplies the appropriate amount of voltage to the interior lamps. When the headlight switch is turned to the PARK or HEADLAMP position, all incandescent back lighting, with the exception of the I/P backlighting, turns ON at the dimming level indicated by the I/P dimmer switch. When the I/P dimmer switch is moved from MIN to MAX, all VF displays, as well as all incandescent back lighting, respond from minimum intensity to maximum brightness in response to the I/P dimmer switch position. The I/P backlight is not integrated in the headlamp switch. The automatic lamp control system must determine if it's dark enough to turn the I/P backlights on. Once the I/P backlighting is turned on, the brightness is controlled by the I/P dimmer switch. In rainy weather, etc., the customer may comment that they manually turned on the headlamps, however, the I/P lights did not come on. It is important to note that the I/P backlight will only turn on when indicated by the Automatic Lamp Control's light sensor. This condition is not related to the headlamp switch function, BCM or I/P function. This is considered a normal condition and no parts should be replaced.
Daytime Running Lamps (DRL)
The ambient light sensor is used to monitor outside lighting conditions. The ambient light sensor provides a voltage signal that will vary between 0.2 and 4.9 volts depending on outside lighting conditions. The body control module (BCM) provides a low reference ground and 5-volt reference signal to the ambient light sensor. The BCM monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lights (DRL) or automatic lamp control (ALC) when the headlamp switch is in the AUTO position. In daylight conditions the BCM will apply ground to the DRL relay control circuit causing the DRL relay coil to energize. With the DRL relay energized, the switch contacts close allowing battery voltage to flow through the DRL fuse via the DRL control circuit illuminating the low beam headlamps at reduced intensity. The DRL control circuit that supplies the low beam headlamp fuses with voltage contains a loop of wire that acts as resistance. This resistance is responsible for the low beam headlamps illuminating at a reduced intensity. Any function or condition that turns on the headlamps will cancel DRL operation.
This is directly from alldata's online manual covering my '09 SS. The 2006 Factory Manual states the same verbiage... verbatim. I was reading between the lines in that the BCM receives a voltage signal from the dimmer switch (BCM X4 connector) then, because it controls the DIC & Radio as stated above, tries to match the dimmer switch's setting at the DIC & Radio. The DIC & Radio display are controlled by the BCM and both are off of the 'Low Speed GMLAN Serial Data bus' as is control for Auto Headlights/DRLs. The Radio does get its back lighting from the dimmer switch, but the actual display is generated via the serial data bus and so is the DIC.
Dimming and backlighting levels are determined by the serial data messages the radio receives. (BCM)
All in all, your way is probably the best compromise at taming the Auto Headlights, rather then my method of disabling them in this manner.
Interior Lamps Dimming
When the ignition switch is turned to the ON position, the VF displays (radio) turn ON at maximum brightness. When the park lamps are ON and the ambient light sensor indicates low light conditions, all incandescent back lighting turns ON at the dimming level indicated by the instrument panel (I/P) dimmer switch. At the same time all VF displays dim to match the indicated dimming level. The body control module (BCM) is responsible for the dimming of the interior lights. The BCM receives a varying signal from the I/P dimmer switch. Based on the position of the I/P dimmer switch, the BCM then supplies the appropriate amount of voltage to the interior lamps. When the headlight switch is turned to the PARK or HEADLAMP position, all incandescent back lighting, with the exception of the I/P backlighting, turns ON at the dimming level indicated by the I/P dimmer switch. When the I/P dimmer switch is moved from MIN to MAX, all VF displays, as well as all incandescent back lighting, respond from minimum intensity to maximum brightness in response to the I/P dimmer switch position. The I/P backlight is not integrated in the headlamp switch. The automatic lamp control system must determine if it's dark enough to turn the I/P backlights on. Once the I/P backlighting is turned on, the brightness is controlled by the I/P dimmer switch. In rainy weather, etc., the customer may comment that they manually turned on the headlamps, however, the I/P lights did not come on. It is important to note that the I/P backlight will only turn on when indicated by the Automatic Lamp Control's light sensor. This condition is not related to the headlamp switch function, BCM or I/P function. This is considered a normal condition and no parts should be replaced.
Daytime Running Lamps (DRL)
The ambient light sensor is used to monitor outside lighting conditions. The ambient light sensor provides a voltage signal that will vary between 0.2 and 4.9 volts depending on outside lighting conditions. The body control module (BCM) provides a low reference ground and 5-volt reference signal to the ambient light sensor. The BCM monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lights (DRL) or automatic lamp control (ALC) when the headlamp switch is in the AUTO position. In daylight conditions the BCM will apply ground to the DRL relay control circuit causing the DRL relay coil to energize. With the DRL relay energized, the switch contacts close allowing battery voltage to flow through the DRL fuse via the DRL control circuit illuminating the low beam headlamps at reduced intensity. The DRL control circuit that supplies the low beam headlamp fuses with voltage contains a loop of wire that acts as resistance. This resistance is responsible for the low beam headlamps illuminating at a reduced intensity. Any function or condition that turns on the headlamps will cancel DRL operation.
Last edited by ScroogeSS; 01-25-2012 at 12:58 AM. Reason: Final Thought
01-25-2012 | 01:03 PM
#93
Senior Member
Joined: 12-24-2008
Posts: 717
From: N/A
Wow, More Than I Wanted to Get Into.
Damn these new vehicles – Nothing is simple!
I had never studied the interior dimming circuit before, but yes the BCM does receive a variable voltage "signal" level via a Voltage Divider* circuit from the rheostat. When you turn the dimming rheostat you change the voltage level sensed by the BCM. This input is then used to put out a reduced "power" voltage level to most of the interior lights in the vehicle. I say most, because as you say the Instrument Panel(IP) does get a digital signal via the Low Speed GMLAN, which tells the IP Module to reduce the light level. Your SS also sends a digital signal via the Low Speed GMLAN to the Radio. My lesser LS may not be the same in respect to the Radio.
There are some conflicts between the Radio Schematic, the Interior Lights Dimming Schematic, the Connector Pin Out Diagrams and the circuit description of the Radio system in my 2009 FSM. My UW5 radio schematic has a wire (circuit 8, color Grey) entering the radio to control the Backlight Dimming. Your, I presume UQ3 radio schematic does not have this wire shown. Both radios have the Low Speed GMLAN in addition. I have found numerous problems with the 2009 FSM so none of this surprises me.
Plus the FSM does not give any description that I can find on just how the radio lights dim.
* FYI, in either case one half of the Voltage Divider is inside the BCM and the other half being either the dimming rheostat or the light sensor on the dash depending upon which input to the BCM is being discussed.
Hope you have no permanent injuries for you foray into the bowels of the dash.
OK, so lets get back to your original question:
Can you clarify just what you are looking for now that things are better understood?
I had never studied the interior dimming circuit before, but yes the BCM does receive a variable voltage "signal" level via a Voltage Divider* circuit from the rheostat. When you turn the dimming rheostat you change the voltage level sensed by the BCM. This input is then used to put out a reduced "power" voltage level to most of the interior lights in the vehicle. I say most, because as you say the Instrument Panel(IP) does get a digital signal via the Low Speed GMLAN, which tells the IP Module to reduce the light level. Your SS also sends a digital signal via the Low Speed GMLAN to the Radio. My lesser LS may not be the same in respect to the Radio.
There are some conflicts between the Radio Schematic, the Interior Lights Dimming Schematic, the Connector Pin Out Diagrams and the circuit description of the Radio system in my 2009 FSM. My UW5 radio schematic has a wire (circuit 8, color Grey) entering the radio to control the Backlight Dimming. Your, I presume UQ3 radio schematic does not have this wire shown. Both radios have the Low Speed GMLAN in addition. I have found numerous problems with the 2009 FSM so none of this surprises me.
Plus the FSM does not give any description that I can find on just how the radio lights dim.
* FYI, in either case one half of the Voltage Divider is inside the BCM and the other half being either the dimming rheostat or the light sensor on the dash depending upon which input to the BCM is being discussed.
Hope you have no permanent injuries for you foray into the bowels of the dash.
OK, so lets get back to your original question:
Now the downside...
The voltage the BCM receives back, controls the odometer/DIC display as well as the factory radio display brilliance. This modification causes these displays to be at full brilliance day & night (you get used to it). The rheostat only controls back-lighting of the instrument panel and instruments. ...Thoughts...?
The voltage the BCM receives back, controls the odometer/DIC display as well as the factory radio display brilliance. This modification causes these displays to be at full brilliance day & night (you get used to it). The rheostat only controls back-lighting of the instrument panel and instruments. ...Thoughts...?
01-25-2012 | 08:56 PM
#94
Member
Joined: 09-27-2010
Posts: 38
From: Yulee, FL
Toast, Bacon, and Scrambled Brains
Oh my! Don't let me stay on the soap box that long again! I believe that we are the only two to dissect a system so thoroughly and still not know how it really works.
The original thought was, how can I tell the BCM to lower the illumination on the DIC & Radio displays... if it is true about the BCM controlling the DIC & Radio displays illumination. I would venture to say it can't be done without some programming changes to the BCM.
Also, I too have the UW5 radio (my SS was a GM exec car, don't know why it has this radio). I know of the 'gray' wire of which you speak. The radio button lighting respond to the rheostat via this wire, its the display itself that remains at full illumination and that's what I was hoping to change given my current diode setup.
The original thought was, how can I tell the BCM to lower the illumination on the DIC & Radio displays... if it is true about the BCM controlling the DIC & Radio displays illumination. I would venture to say it can't be done without some programming changes to the BCM.
Also, I too have the UW5 radio (my SS was a GM exec car, don't know why it has this radio). I know of the 'gray' wire of which you speak. The radio button lighting respond to the rheostat via this wire, its the display itself that remains at full illumination and that's what I was hoping to change given my current diode setup.
01-25-2012 | 09:42 PM
#95
Senior Member
Joined: 12-24-2008
Posts: 717
From: N/A
The original thought was, how can I tell the BCM to lower the illumination on the DIC & Radio displays... if it is true about the BCM controlling the DIC & Radio displays illumination. I would venture to say it can't be done without some programming changes to the BCM.
01-26-2012 | 11:23 AM
#96
Senior Member
Joined: 11-14-2006
Posts: 132
From: Memphis, Tn
Has anyone had issues with one side of there HIDs quickly shutting off when turned on with the automatic system? This is always on the passenger side. If I let the auto system turn on the headlights (when I turn on the ignition) they both fire but the passenger side quickly shuts off. I have to turn them off and on a couple times to get it to fire. It almost seems as if the auto system doesn't have the power to fire each ballast upon startup with the ignition.
-NOW-
If I turn the headlights on before I turn the ignition on they fire up as they should. With the HIDs already on I get no issues when I turn the ignition on either. What gives?
2007 LT with factory fogs
DDM 35w 5000k hi/lo (wired properly and grounded properly to bare metal)
DRL fuse has been pulled
low beam fuses have been bumped 5amps (which did nothing)
-NOW-
If I turn the headlights on before I turn the ignition on they fire up as they should. With the HIDs already on I get no issues when I turn the ignition on either. What gives?
2007 LT with factory fogs
DDM 35w 5000k hi/lo (wired properly and grounded properly to bare metal)
DRL fuse has been pulled
low beam fuses have been bumped 5amps (which did nothing)
01-26-2012 | 04:58 PM
#97
Senior Member
Joined: 10-13-2009
Posts: 186
From: sterling hts mich.
I think DRL's are a great idea but on my '09 I would like to have my running lights instead of the headlights. Right now I turn on my fog lights and the headlights go out and the running lights come on. This is how I run everyday since my son showed me this.
01-26-2012 | 11:21 PM
#98
Senior Member
Joined: 06-25-2008
Posts: 305
From: Austin, TX
Has anyone had issues with one side of there HIDs quickly shutting off when turned on with the automatic system? This is always on the passenger side. If I let the auto system turn on the headlights (when I turn on the ignition) they both fire but the passenger side quickly shuts off. I have to turn them off and on a couple times to get it to fire. It almost seems as if the auto system doesn't have the power to fire each ballast upon startup with the ignition.
-NOW-
If I turn the headlights on before I turn the ignition on they fire up as they should. With the HIDs already on I get no issues when I turn the ignition on either. What gives?
2007 LT with factory fogs
DDM 35w 5000k hi/lo (wired properly and grounded properly to bare metal)
DRL fuse has been pulled
low beam fuses have been bumped 5amps (which did nothing)
-NOW-
If I turn the headlights on before I turn the ignition on they fire up as they should. With the HIDs already on I get no issues when I turn the ignition on either. What gives?
2007 LT with factory fogs
DDM 35w 5000k hi/lo (wired properly and grounded properly to bare metal)
DRL fuse has been pulled
low beam fuses have been bumped 5amps (which did nothing)
From what I've heard, it's a fairly common problem, not isolated to HHRs. I think someone suggested installing a relay to the offending side to help get the required power to the bulb.
01-26-2012 | 11:30 PM
#99
Platinum Member
Joined: 01-09-2007
Posts: 15,983
From: SE USA
I live in a rural area and when driving on the posted 55mph 2-lane roads, I find that when I have a vehicle with DRLs (or a vintage one that I turn the headlights on), idiots are less apt to pull out on me when I'm just upon them.
Not a big deal in town, but I like them on the backroads.
Not a big deal in town, but I like them on the backroads.
05-09-2012 | 03:10 PM
#100
Senior Member
Joined: 11-14-2010
Posts: 256
From: Louisiana
I just don't like the lights on all the time (DRL)... even at reduced intensity.. Maybe I just want to save light-bulbs? Maybe I just want "control"?
As far as Auto-headlamps--I like them! But if I need to disable them to make the DRL's non-functional, it's OK...
Just a little quirk I have, I guess...
As far as Auto-headlamps--I like them! But if I need to disable them to make the DRL's non-functional, it's OK...
Just a little quirk I have, I guess...