josua
Seasoned Member
Auto headlight just quit working. Is there a fuse for this? The fuse panel doesn't show any. Anybody else had this problem. The manual switch works, but the auto doesn't. Nothing's blocking the sensor.
Automatic headlight
- Thread starter josua
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mickeytee
Seasoned Member
The IntelliBeam system can be disabled by the High/Low-Beam Changer or the Flash-to-Pass feature. If this happens, the High/Low-Beam Changer must be activated two times within five seconds to reactivate the IntelliBeam system. The instrument cluster light will come on to indicate the IntelliBeam is reactivated
Read more: Cadillac IntelliBeam: What It Is, How It Works | GM Authority
Read more: Cadillac IntelliBeam: What It Is, How It Works | GM Authority
ccclarke
Seasoned Member
The Intellibeam feature first appeared on the 2005 STS, then re-appeared in its present form on the 2013 XTS, six months into the production run. It became more common in Cadillac models the following year.
XLR production ceased in 2009 and inexplicably never received it. Similar function Autotronic headlights first appeared on 1952 Cadillacs.
Even if Intellibeam was available on the XLR, it doesn't turn on the headlights automatically; it only affects high-beam operation.
Intellibeam automatically switches between high and low beams when a sensor on the front of the mirror detects head or taillights. It's a nice safety feature to prevent those "Doh!" moments and is migrating throughout GM's model portfolio.
Back to the issue the OP needs help with:
The XLR uses a Sunload/Twilight Sentinel sensor, located on the top of the dashpad, which measures ambient light levels (when the headlamp switch is in Auto mode) to enable/disable the headlamps automatically.
The ambient light sensor sends a voltage (proportional to how much light it receives) to the HVAC control module which places a status signal on the Class 2 data bus that is picked up by the Body Control module to turn the headlamps on and off.
Since the symptoms you describe indicate the headlamps can be switched ON manually but not in Auto mode, most of the circuit from the BCM to the lights appears to be working properly.
This leaves three components most likely to be suspect (if the wiring paths are good): The light mode switch, the Sunload/Twilight Sentinel Sensor, and the HVAC control module (the center console AC unit).
To troubleshoot this failure quickly and easily without having to take stuff apart, a Tech 2 scan tool is required.
--If substantial alcohol consumption is an issue, a Tech 2 turns what could easily be a twenty-four beer job into a single can or bottle.
(The alternative to using a Tech 2 is disassembling the interior to access connectors to make voltage measurements where applicable, requiring copious amounts of beer.)
When it performs the Lighting System Diagnostic check, The Tech 2 can display if the Auto switch is operating as it changes modes while manually-operated.
There's a separate check to view the HVAC data list that displays the ambient light sensor values. They will change when the sensor is exposed to light and then covered. (If the ambient light level circuit is malfunctioning, a DTC error code of B2646 will pop up.)
If the light sensor is working but this code is displayed, then the HVAC module is suspect.
As expensive as shop labor rates are and as cheap as Tech 2's are becoming, (especially the Chinese clones which can be had for $250) if you're planning to keep your XLR, they're a worthwhile investment if you are a reasonably competent DIY'er. You will also need access to the Service manuals to understand what the scan tool is describing while you follow the troubleshooting paths.
CC
XLR production ceased in 2009 and inexplicably never received it. Similar function Autotronic headlights first appeared on 1952 Cadillacs.
Even if Intellibeam was available on the XLR, it doesn't turn on the headlights automatically; it only affects high-beam operation.
Intellibeam automatically switches between high and low beams when a sensor on the front of the mirror detects head or taillights. It's a nice safety feature to prevent those "Doh!" moments and is migrating throughout GM's model portfolio.
Back to the issue the OP needs help with:
The XLR uses a Sunload/Twilight Sentinel sensor, located on the top of the dashpad, which measures ambient light levels (when the headlamp switch is in Auto mode) to enable/disable the headlamps automatically.
The ambient light sensor sends a voltage (proportional to how much light it receives) to the HVAC control module which places a status signal on the Class 2 data bus that is picked up by the Body Control module to turn the headlamps on and off.
Since the symptoms you describe indicate the headlamps can be switched ON manually but not in Auto mode, most of the circuit from the BCM to the lights appears to be working properly.
This leaves three components most likely to be suspect (if the wiring paths are good): The light mode switch, the Sunload/Twilight Sentinel Sensor, and the HVAC control module (the center console AC unit).
To troubleshoot this failure quickly and easily without having to take stuff apart, a Tech 2 scan tool is required.
--If substantial alcohol consumption is an issue, a Tech 2 turns what could easily be a twenty-four beer job into a single can or bottle.
(The alternative to using a Tech 2 is disassembling the interior to access connectors to make voltage measurements where applicable, requiring copious amounts of beer.)
When it performs the Lighting System Diagnostic check, The Tech 2 can display if the Auto switch is operating as it changes modes while manually-operated.
There's a separate check to view the HVAC data list that displays the ambient light sensor values. They will change when the sensor is exposed to light and then covered. (If the ambient light level circuit is malfunctioning, a DTC error code of B2646 will pop up.)
If the light sensor is working but this code is displayed, then the HVAC module is suspect.
As expensive as shop labor rates are and as cheap as Tech 2's are becoming, (especially the Chinese clones which can be had for $250) if you're planning to keep your XLR, they're a worthwhile investment if you are a reasonably competent DIY'er. You will also need access to the Service manuals to understand what the scan tool is describing while you follow the troubleshooting paths.
CC
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josua
Seasoned Member
Fixed
Now its working. Probably something I did
Now its working. Probably something I did
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