Cadillac Owners Forum banner

1 - 8 of 8 Posts

·
Registered
2006 DTS
Joined
·
9 Posts
Discussion Starter #1
Hi everybody, I've been a member here for awhile, but this is my first post. I have a 2006 DTS with about 68k miles. So I am having an issue, lately that I hope someone may be able to help me with because I'm frustrated enough to just drive the damn car into a tree at this point. So my passenger side headlight has been having an issue where it will intermittently turn off. My first thought was that the bulb was bad, so I replaced both headlight bulbs. After doing this the problem persisted. My next step was then to replace the passenger side ballast. After doing this, the headlight still continued to turn itself off. Since then, I have also tried a couple of other bulbs thinking that maybe my new bulb happened to be bad, but still the same problem. I should mention that before replacing the ballast the high-beam solenoid on the passenger side did not work properly, but replacing the ballast corrected this. At this point, I'm not sure what else to do to correct this. Could this possibly be an issue with the BCM, headlight switch, or twighlight sensor for the headlights? If it was a problem with one of these things wouldn't it cause an issue in both headlights, and not just the passenger side? On a possibly related note, I had an issue with my dashlights the other night. I was driving home with the auto lights on, the headlights, and all of the dashlights turned on, but the lights in the NAV didn't light up, and the NAV screen didn't change to the night time view. I turned the headlights off, and back on, and this corrected the problem, the NAV lights lit up, and it went into night mode. Also recently, the interior lights no longer turn on when the front passenger side door is opened, they work properly with every other door. I hope someone is able to give me some suggestions on this because I am about at my last nerve with this car. Thanks in advance for the help.

----------

Also I forgot to mention one other thing. With the lights turned to auto, if I turn the wipers on, the headlights do not turn on. I was told that they should turn on automatically with the wipers on.
 

·
Registered
2011 DTS Platinum
Joined
·
4,633 Posts
The wipers have to run for a few seconds before they automatically turn on the headlights...
When the headlights come on... the blue headlight symbol beside the tach will also come on...

Sorry I can't help you with the electrical issue...
You have already replaced the ballast and bulb, which is what I would have suggested...
I would suspect you have a loose wire or wires somewhere that is affecting the passengers side of the car..

Texas Jim
 

·
Registered
2006 DTS
Joined
·
9 Posts
Discussion Starter #3
Interesting about the wipers, no matter how long I wait, my headlights never turn on. Also I don't have a blue headlight symbol on the dash. I only have two greens ones, one that indicates when the parking lights are on, and one for the foglights, but nothing for the headlights. This makes me wonder if the issue with the headlight turning off could be caused be a bigger electrical issue.
 

·
Registered
Joined
·
757 Posts
HEADLIGHT.gif

Headlamp Operation

The low beam headlamps may be turned ON in 3 different ways:
1 When the headlamp switch in the HEAD position for normal operations

2 When the headlamp switch is in the AUTO position, for automatic lamp control (ALC)

3 When the headlamp switch is placed in the AUTO position, with the windshield wipers ON in daylight conditions, after a 6 second delay

Do you have water in the headlamp The Headlamp Ballasts have been updated al least 5 times. You can try swapping the left for the right ballast.
Also do the same for the cable from the ballast to the bulb. Look at fuses F2, F3 for discolor and proper fit
I put up a pic of the Schematics for the headlights


The Ambient Light Sensor is working because the Courtesy lights come on with the other doors. The DDM driver’s door module talks to the BCM
. You may try Taking both battery cables off and hold them together for 10 sec to see if it resets the DDM and BCM
 

·
Registered
2006 DTS
Joined
·
9 Posts
Discussion Starter #5
I just thought I would give an update because I hate when people post a problem, but never post what the final solution was. As far as my headlight was concerned, it ended up being a combination of things that made it a bit hard to track down. It turns out that I initially had a bad ballast and bulb on the passenger side. It also turns out that when I bought new bulbs, one of the new bulbs was bad out of the box, and I just so happened to put it on the passenger side making things a bit more complicated and confusing. The bulbs were cheap ones from DDM Tuning, so that's what I get for going cheap. In the end, I replaced the passenger side ballast, and both bulbs with new Osram Xenarc CBI bulbs, and everything seems to work great.

As for my other issue, my interior lights not coming on when opening the front passenger side door, I still haven't figured this issue out. I did reset my BCM, which actually fixed an issue I was having with the tilt feature on the driver seat, but it didn't do anything for the lights not coming. I am assuming the issue is with the door jam switch, but for the life of me I can't seem to find it. On every other car I have ever owned, it has been a spring loaded button somewhere in the door opening, but there doesn't seem to be one on this car. Any insight would be appreciated.
 

·
Registered
Joined
·
757 Posts
DRIVERS DOOR.gif DRIVER DOOR MODULE.gif

Most cars are built around a networks system now. GM calls it the GMLAN.
It has a High speed and low speed LANs, as well as the Local Interconnect Network.

With the Tech 2 we could find the problem in no time.


IN the drivers door pic #10 Drivers Door Latch Assembly Takes the place of the old spring switch. Jim was right


Courtesy Lamps


When either one of the front doors is opened, ground is applied through the door latch door open switch and the door open switch signal circuit to the door module indicating the door open position. In response to this signal, the door module sends a GMLAN serial data message to the BCM of the door open position. Or, when either one of the rear doors is opened, ground is applied through the rear door latch door open switch and the rear door open switch signal circuit to the BCM indicating the door open position. Once a door open message or signal is received, the BCM will then apply battery voltage from the CTSY/RF TRN fuse through the courtesy lamp supply voltage circuit illuminating the lamps listed below. At the same time the BCM sends a GMLAN serial data message to the driver door module (DDM) and the front passenger door module (FPDM) indicating the courtesy lamps ON request. In response to this message, the door modules apply battery voltage to the courtesy lamp supply voltage circuits illuminating the front door courtesy lamps. The front door modules also provide a ground through the low reference circuits to the courtesy lamps.

Local Interconnect Network (LIN) Description


The driver door module (DDM) and the front passenger door module (FPDM) communicate with window motors on the local interconnect network bus 1 and the local interconnect network bus 2 circuits respectively. The DDM LIN buss is connected to all window motors on its side of the vehicle, while the FPDM LIN buss is connected to the other window motors. Communication on this network is only between the door modules and the window motors. The window motors are in effect modules. The window motor modules do not communicate on any other data buss; therefore the door modules, which also communicate on the low speed GMLAN serial data buss will perform all communication with each other, the motors, the body control module (BCM) (gateway) and the scan tool including setting LIN buss DTCs.
 
Joined
·
12,821 Posts
I just thought I would give an update because I hate when people post a problem, but never post what the final solution was. As far as my headlight was concerned, it ended up being a combination of things that made it a bit hard to track down. It turns out that I initially had a bad ballast and bulb on the passenger side. It also turns out that when I bought new bulbs, one of the new bulbs was bad out of the box, and I just so happened to put it on the passenger side making things a bit more complicated and confusing. The bulbs were cheap ones from DDM Tuning, so that's what I get for going cheap. In the end, I replaced the passenger side ballast, and both bulbs with new Osram Xenarc CBI bulbs, and everything seems to work great.

As for my other issue, my interior lights not coming on when opening the front passenger side door, I still haven't figured this issue out. I did reset my BCM, which actually fixed an issue I was having with the tilt feature on the driver seat, but it didn't do anything for the lights not coming. I am assuming the issue is with the door jam switch, but for the life of me I can't seem to find it. On every other car I have ever owned, it has been a spring loaded button somewhere in the door opening, but there doesn't seem to be one on this car. Any insight would be appreciated.
Cmcdonald, thank you for posting your updates for the benefit of the community! I realize you're seeking DIY advice (in which case, it's great Jim & Danog replied again with feedback), but please keep me in mind if you decide to involve your dealership at any point. I'm always happy to contact them on your behalf to schedule appointments or follow up on concerns; don't hesitate to email me at [email protected] for further assistance.

Best,

Katie
Cadillac Customer Service
 
1 - 8 of 8 Posts
Top