Door switches and remote will not lock doors

[NMBurb02]

The doors on my 2006 Pontiac Grand Prix will no longer lock using either door switch or the keyless entry remote. Pushing the switch to "lock" or pressing the lock button on the remote will result in a single click in the dash, but the door locks will not engage, but the alarm will arm. I have the auto lock setting (where the doors lock when you begin to drive away) active, but they do not lock then either. The door switches and remote will still unlock the doors and pop the trunk (by holding it in the "unlock" position), turning my power door lock feature in a power unlock only feature.

I have checked the door lock fuse and it is intact. I deactivated the door lock delay feature (if you press the door switch to "lock" a single time, a chime sounds, and the door does not lock for a few seconds) through the DIC and the doors locked the next time I pressed the switch! I then unlocked the doors and tried to lock them again, but with no luck. I reactivated the door lock delay feature and tried again, with no success, and then deactivated it again, but it will not repeat its one-time lock trick.

This is an inconvenience that I can deal with, but it gets tiresome when I have to pop the trunk using the door switch (my wife has our only remote), manually lock each door from the inside, and then lock and close the drivers door.

Can anyone shed light on what may be going on and what can be done to fix it? I have done some Googling on the matter and nobody seems to be able to fix this issue with GM door locks, not even the dealerships. Could this be related to the ignition cylinder issues resulting in the recall?

Edit: This started out as an intermittent problem a month or two ago but now seems here to stay. I would blame it on the weather getting cold, but we are still getting into the 80s and 90s here.

 

[Trav]

I think it could be related to the ignition. when you turn the key off, put it in park/drive the doors unlock and lock so it is connected to the BCM.
If it has recall get that done first before condemning the BCM.

 

[Delta]

Have you looked into the door lock actuators themselves? Our 2008 Equinox is experiencing the same issues, except the drivers door. 95% of the time the key fob or lock button on the door will not lock them. They will unlock the doors, but not lock most times. Also the auto lock feature going into drive does not function normal, only the good actuator will lock. Dealer said the lock actuators are/going bad. Once in a blue moon they will all function normal, then the next run cycle, nada. They wanted about $300 a door so I said forget it since I'm dumping the vehicle within a year.

 

[HerrStig]

Does this car use a "CAN Bus"? Switching is done by commands from a body control computer in that case. All sorts of new things to go wrong. The switching signal rides on the common power supply wire. Better get a shop manual.

 

[Kuato]

Originally Posted By: Delta
Have you looked into the door lock actuators themselves? Our 2008 Equinox is experiencing the same issues, except the drivers door. ..


If that was the case, would all 4 doors quit at once?

I'm thinking wiring or a ground is loose, and would trace from where you get the click under the dash. It've also read where it was the driver's door control pad.

 

[NMBurb02]

Well, the locks worked tonight! But I doubt they will tomorrow...

However, I will try them out again tomorrow to see how they do.

 

[meep]

it is either:

1. lock relay (the 'click' under the dash)

2. loose wiring (unlikely)

3. bad lock switch (based on your description, unlikely)

4. worn lock motors. highly likely.

 

[01rangerxl]

Originally Posted By: Trav
I think it could be related to the ignition. when you turn the key off, put it in park/drive the doors unlock and lock so it is connected to the BCM.
If it has recall get that done first before condemning the BCM.


Unfortunately the only current recall that applies to his car, unintended key rotation, will only get him new inserts or a cover on the keys. The recall just makes the hole for the key ring smaller. No part changes on the car itself.

My theory is that the Pass Key strip on the ignition switch is worn out and is not detecting that the key is out of the ignition. It thinks the key is still there, so it is trying to do you a "favor" by refusing to lock the doors electronically. This strip can also fail the other way and refuse to allow the car to start. Does the door chime sound at all when you hit the lock button? I think it would if this is what is wrong, but I am not positive on that...could vary by model.

The Pass Key strip ("module") is attached to the ignition cylinder, but can be purchased separately and many GM dealers will have it in stock. It lists for about $140. I believe the part number is 15785406 for your car, but you should have that confirmed by the VIN number (if you PM me the last 8 digits I can check)...and that is just my theory, not 100% absolutely beyond a doubt what is wrong.

 

[NMBurb02]

Originally Posted By: 01rangerxl
Originally Posted By: Trav
I think it could be related to the ignition. when you turn the key off, put it in park/drive the doors unlock and lock so it is connected to the BCM.
If it has recall get that done first before condemning the BCM.


Unfortunately the only current recall that applies to his car, unintended key rotation, will only get him new inserts or a cover on the keys. The recall just makes the hole for the key ring smaller. No part changes on the car itself.

My theory is that the Pass Key strip on the ignition switch is worn out and is not detecting that the key is out of the ignition. It thinks the key is still there, so it is trying to do you a "favor" by refusing to lock the doors electronically. This strip can also fail the other way and refuse to allow the car to start. Does the door chime sound at all when you hit the lock button? I think it would if this is what is wrong, but I am not positive on that...could vary by model.

The Pass Key strip ("module") is attached to the ignition cylinder, but can be purchased separately and many GM dealers will have it in stock. It lists for about $140. I believe the part number is 15785406 for your car, but you should have that confirmed by the VIN number (if you PM me the last 8 digits I can check)...and that is just my theory, not 100% absolutely beyond a doubt what is wrong.

I have the car set to unlock the driver's door when I remove the key and it still does that, so it knows that the key is no longer in the ignition.

 

[01rangerxl]

Hmmm...could be a deeper issue in the body control module itself then.

GM only sells the BCM as remanufactured units, and availability tends to be spotty since it is based on having cores. Should be about $240 for the part (not including any programming if required, not sure on this car).