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Buick LaCrosse Electrical/Lighting Problems



  • I would start with the HDM module, this seems to be a coomon problem on these model year Buick's. You can get them from Autozone or Advance Auto Parts, simply remove your old one and take it in, the unit will have the original GM part # on it that they can cross reference against their aftermarket part. let me know if this works. Good luck!
  • e_net_ridere_net_rider Posts: 1,380
    It would seem highly unlikely, but I actually had broken filaments in both low beams. What likely made it difficult is they were intermittant. And if I touched the connector they would reconnect making me think it was actually a connector problem.
  • I first noticed the problem about 4 months ago. My low beam headlights went out while driving at night, and it took a few minutes for them to come back on. High beams worked. It didn't do it again for about a month. Now the problem is that if the car sits for a long time (approximately 12 hours) it won't start. I replaced the battery because I was informed my old one was bad. I have had the altenator tested, and it is good. However, someone told me that there is something on the side of the altenator that could go bad and there is no way of testing it and the only way to replace it is by getting another altenator. I have also been told there is a possible short or the body control module. I have noticed that when you turn the car off, and before you open the doors the radio will go off then come back on then go off and then back on. I know the radio is supposed to stay on for awhile before going off on its own and staying off but this doesn't do that. Also the lights for the heater (the ones that light up the sides to control the temperature and along the bottom, not the ones that illuminate in the middle showing actual temp) flashes off and on. Not continously but approximately every 5 minutes. This happens even when the car is off, the keys removed, the door has been opened and closed (and I am assuming all night, I haven't sat all night to watch it). The radio and heater also glows an orange/red light after being turned off and I have gotten out of the car. Eventually it goes off. About a month ago, my heater/ac fan started acting up. At first it started out as being off and on. Sometimes you would get in the car and it would work. Then it quit for about 2 weeks and wouldn't work at all, then one morning I got up and accidentally turned it on and it worked and has been working ever since. I have to always check my battery voltage to be sure it will start. If it falls below 11.2 it won't start. When I jump start it, it is easy to start. You don't have to let it sit and charge for a while before it will start, usually hooking the jumper cables up to both cars will make it start. It has become unreliable, and I am afraid to go anywhere and stay for a while. I can unhook a battery cable and then hook it back up but that is aggravating. Anyone have any ideas? or this problem? Thanks.
  • gmcustsvcgmcustsvc Posts: 4,251

    I apologize for the problems you are experiencing with your vehicle. Were you planning on having the vehicle diagnosed by a GM dealership? Please keep me posted.

    Thank you,
    Caron, GM Customer Service
  • Although weirdness like this was occuring in 95-99 Aurora, although such functioning was controlled by the BCM it turned out to have a different root cause.
    Again, this vehicle may be quite different.
    The problem was caused by the multifunction switch on the column that controlled high/low beams, etc. The grease in the switch seemed to be drying out and caused it. Many took their vehicle to dealer and had the column wiring harness replaced at an expense of $500 and up. Someone figured out that washing the switch out with solvent and contact cleaner cured the issue. I can testify that it worked. If you decide to try such, be prepared for a mess with lots of absorbent material, towels, etc.

    Good Luck
  • The guy that told me it was a short or the BCM is a certified GM mechanic. I am seriously thinking about getting rid of the car. Thanks for your responses. I appreciate it.
  • The guy that went into my freon system and changed expansion valve when it was obvious the problem was related to the electronics or control of the heater core/evaporator control door is a certified GM mechanic.
    I can only guess if he was following GM written procedure, received a bad expansion valve, or was working mainly in the profit interest of the dealership.
    The saleswoman at Cadillac dealership claimed to be certified knowledgeable. She was pushing the OnStar system saying the minutes were cheap, claiming it worked off satelite, SATTCOMM, and got indignant when I tried to correct her that the phone works off cell system. She actually stormed away.
  • On my way to VA yesterday, a new gremlin popped. Both hands on steering wheel, it started getting hot for about 2 minutes. The only explanation is the heat turned itself on for about that length of time.
    Control head or pinched wire? Remember, the column was changed. And since then there has been the play in the steering and also a nagging question as to whether the magnasteer is working or not. That is the electro-mechanical device that adds steering effort the faster you go. That is any input from the road toward the steering wheel should be reduced proportionally the faster you go.
  • update. I drove to gas station to get a couple of packs of cigs, about 2 miles.
    On the way it occured to me to try the wheel heater. It started to heat, but I was almost there already. Turning it on again when I left, no heat at all, all the way home. Indicator light came on and stayed on.
  • dminerdminer Posts: 3
    What was the part number, my wife has the same problem, I asked aobut the light relay and was informed that there is only a high beam light relay.
  • The "volt" light on my dashboard keeps coming on and off intermittently, although the alternator tests good for charging. My mechanic has replaced the alternator twice in the last 10 days and it still happens, so he's going to replace it with yet another one. He says the sensor that turns this light on, is inside the alternator. My Haynes manual shows the wiring going from the negative side of the light to the PCM, not direct to the alternator. Can somebody please help me, and perhaps tell me where I can get a GM wiring diagram specific to my car? Thanks!
  • gmcustsvcgmcustsvc Posts: 4,251
    We can also look into this for you with your VIN and more information about the part that you are seeking. Please feel free to contact Christina by email for more assistance. Thank you.

    Tricia, GM Customer Service.
  • dminerdminer Posts: 3
    What is Christina's email address?
  • I looked up my service record. The exterior lighting relay was replaced on 5/29/09.
    We have not had the problem since. Our car is a 2006 LaCrosse CX. The part number for the relay that was installed is: 15016745 . Hope this can help ! Also this relay could be called a fog lamp relay ( daytime running lights). When the problem
    occurs, the daytime running lights did not work during the daytime.
  • Hope I didn't confuse the issue. The low beam headlights didn't work either. No daytime running lights in daytime. No low beam headlights manually or auto - day or night. Key fob didn't flash exterior lights either.
  • dminerdminer Posts: 3
    I am going to give it a try, thank you for all your help. I hope this works. Thank you again!
  • gmcustsvcgmcustsvc Posts: 4,251
    It is in my user profile, just click on my user name.
    GM Customer Service
  • alchipalchip Posts: 18
    Our 2006 LaCrosse CX has a dimly lit digital odometer in the dashboard. The mileage display is only half lit and it is virtually impossible to see during the day. Is there any way to affordably fix this? I called a shop today and they gave me a rough estimate of $ 550 because they said the odometer is really a light strip which would need replacement, and of course, the dash would have to be removed. Seems like a lot just to easily read the mileage! Thanks.
  • I am having a similar problem with my 2011 Buick Lacrosse CXS that was purchased brand new. This problem occurred around 5,000 some odd miles in February of 2012 and it is now August of 2012. My car has been in and out of the dealership over numerous days. (It will be a total of around 48 days now, which is completely ridiculous.) It has died on the highway twice with no electronics/brakes/steering, putting my safety in danger as well as others. The car is also having problems not starting and has been a frequent problem. The dealership has replaced body control modules, frayed wires under the steering column, key less entry modules, and media center modules. GM is clearly trying everything in the book to avoid classifying it as a lemon. Mind you, this car has also had quality assurance issues such as the bumper being misaligned with the vehicle, the back covers of the entertainment system DVD seat covers popping off, plastic of console coming off, and a rattling in the wheel well brake shield covers. This car is brand new and has been having all of this issues! There is no reason for a vehicle to be brought into service that many times! So with that said, I have began to documenting everything very closely. I have written a letter to GM demanding the buyback of the vehicle along with explaining all of the problems and concerns. (remember to keep copies of everything) I also went to BBB Autoline to file a complaint as I am working with them diligently. The manufacturer still has yet to do anything but try and "diagnose" the vehicle for problems that keep occurring. I am now using the lemon law to fight them! It has clearly gotten out of control with their lies and I am tired of it. I should not pay for a car that does not deliver what is promised and puts me and others in an unsafe, unreliable predicament. I will now be using the Magnuson-Moss Warranty Act under the Texas lemon law to finally put a stop to this. If you do not fight for yourself these companies will continue to deliver poor customer service and promises to a naive consumer who trusts them! It's time to do something about it, and I will!
  • alchipalchip Posts: 18
    So sorry to hear of your troubles. Actually, we really like our LaCrosse. I'm just looking for an affordable way to read my mileage again!
  • Yeah it is a shame indeed, a shame that GM DIDN'T listen to their customer... Don't get me wrong I love the car... it's just one of those... and one of those companies that obviously doesn't care.
  • e_net_ridere_net_rider Posts: 1,380
    Sorry for both of you. The lighting is controlled with dimmer circuitry. I think that includes the mileage reading. Do you have HUD? NAV is included on the CXS if I remember correctly.
    Anyway, the different lights would require different variables to keep the sources approximately the same level. That is likely a panel with several controllers run in parallel from the dimming control. It sounds like the possibilities are that the circuit for mileage inside that box could be bad. The output from it is wired to the dash group including the mileage readout.
    So three possibilities. The controller box, wiring, and/or the unit containing the readout. It should not require removing the entire dash to replace the units, but the wiring is a different situation. That is, it depends upon what GM requires as a warranty fix.
    And there is a big part of the rub. It might require replacing a major wiring harness. The more that is taken apart, the greater the chance of something else being broken. That is the mechanic would be required to follow GM procedure, but may not. GM procedure could be incorrect, written by some nummy who may have never laid a hand on a vehicle, and thinks that the same procedure for a different vehicle will work. Frustrating the mechanic, who may be under trained/experienced, you may get a botched job. But he will certainly try to make sure the dealer gets paid and anyway possible attempt avoiding a free re-work. And somehow the GM know-it-alls go along with that. They are so smart that GM and any of its parts make no mistakes. (That was the attitude I percieved from the GM district rep, even when you could clearly show him the difference between yours and a working vehicle.) Alas, GM also took the attitude that if they are alike then it is not broken. Reality being they are all broken.
    Hope this helps in determining if they have been trouble-shooting properly or changing correct components, etc.
    BTW, see if the boots on your rear shocks have fallen and see if you can get them to fix. Please report back. The issue is that the fallen boot will lead to early failure of shocks, albeit maybe not until after warranty is expired. And if you have the touring package, that might be a very expensive job because of the full time electronic suspension.
  • uickuick Posts: 1

    worked like a charm

    saved me a few bucks for not taking it to a mechanic
  • Thank you.

    I had the same problem for 1 year. The headlinght on for awhile then off then back on. I just replace the HDM module relay at position #35 and it work good now. It cost $38 from Auto Zone.
  • kctran,

    Thanks for taking the time to post , I am happy knowing my post helped some folks out and saved them a few bucks as well.
  • Just got a 2011 lacrosse csx they tell me just push the fog lamp button when the lights are on and in auto they will always come back on.
    Guess what they do not.. If i shut the car off and turn it back on with in 30 sec they do but if i go in the house or store work when i come back out turn on the car just the headlights come on.Think it's cool how you see the headlights go through there test by moving right to left i see them on my garage door.What i'm trying to find out should they come on after doing what i'm told about pushing the button when the lights come on Thanks
  • e_net_ridere_net_rider Posts: 1,380
    I don't remember exactly, but I think they went off. Check your manual to be certain and if you can find them, download a pdf version which is very searchable.
    One of the nice points is the button to turn on. A large round button that only takes a tap to activate and is easy to locate by feel so no time "eyes off the road" needed. Wish my MKS worked that way. Large round button, but have to pull-push for on/off.
    BTW, does yours have the fallen down boots on the rear shocks?
  • gmcustsvcgmcustsvc Posts: 4,251
    Good morning and congratulations on your 2011 LaCrosse! We hope you're enjoying your vehicle so far!

    In regards to the fog lamps, if the fog lamps are turned on while the exterior lamp switch is in the AUTO position, the headlamps come on automatically (p.6-5 in the manual). Looking at the section on the automatic setting for headlamps, it does not seem to affect the fog lamps.

    If you do have further questions about your new vehicle, we'd all be happy to help!

    All the best,
    GM Customer Service
  • If the fog lamps are turned on while
    the exterior lamp switch is in the
    AUTO position, the headlamps
    come on automatically.
    They come on if i turn off car for more than 5 minutes they will not come on until i push the button again.This is what i do not want to do everytime i get in the car. could you ask a mechanic if a relay could be faulty.Thanks
  • tjc78tjc78 JerseyPosts: 6,652
    My 2012 is the same way.

    You do know it is not preferred to drive with fogs on all the time correct?

    The short throw of the lighting directs your attention from further down the road.

    This can explain it well. DanielStern Lighting

    2017 Buick Enclave / 2017 Hyundai Elantra

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