Gents; My boy's 2009 Aura's locks and trunk latch are not working with any switches nor the remote. However, the locks will "try' to work when put in or out of park. I've checked the fuses and they are ok. Before I start tearing into the doors and such, have any of you gents had a problem like this and could give me a hand? Thanks

 

Is the check engine light on?

Did both of these stopped working at the same time?

 

No check engine light but there is a low pressure tire light on....that's another issue though. I try to keep my boy's Saturn running ok but over the years it's proven to need almost constant attention,.....wiring issues, pulled the front bumper to change a head light bulb, cv axle replacement, many cylinder misfire lights brake lights off and on and on. Mean time my old 2007 Hyundai with over 200K miles keeps going with minimal issues. Are American cars that bad? Don't know what u r salutation means but I like it!

 

Please provide an answer to my second question so that we may proceed with an attempt to troubleshoot

 

Seems like the door locks and trunk latch stopped working at the same time....I need a wiring diagram but those r hard to come by.

 

I believe the request to operate both of these is sent to and processed by the BCM (body control module).

The fact that both make the "sound" of actuating but do not actuate leads me to believe that they are able to communicate with the BCM, but what the BCM sends as a control signal depends on what it receives from the component.

As this happened simultaneously, I would lean towards a bcm or wiring related problem. The trunk latches on these cars are known to become misaligned and will hang up while trying to unlock. There is also a relay for the trunk latch that you can check.
If your trunk light does not work, there may be one or more broken wires in the harness that runs along the inside of the trunk. The breaks are often at the bend point.

I would get a hold of a code scanner that can read body control codes , B codes. The body control module will store these codes when malfunctions are detected. However, they do not eliminate the check engine light because they are not related to emissions and such. The standard code read at AutoZone does not include scanning for B codes.
Pulling these codes or verifying that none are there should help you with regards to diagnosis.

In the end it could be as simple as losing a ground connection somewhere. I agree the wiring diagrams will be of great help. No promises, but I will go and dig for some.

 

Agreed 100% derf. Looks like I need either one of those fancy scanners that can read the BCM or a wiring diagram. Since the diagram will b the cheapest but admittedly take longer, I'll dig more for a wiring diagram but if you could find one derf, it would b appreciated. Thanks

 

These code scanners are not nearly as expensive as they used to be. Some are Bluetooth dongles that can be attached to the OBD2 port on the vehicle and the codes read through your cell phone.

Others are standalone units. You will also want to have a scanner that supports manufacturer specific codes.

Another option is to take the vehicle to a facility and pay for a diagnostic. This costs about as much as one of the very nice Bluetooth dongles. Also, some repair facilities will not give you the actual codes that they pulled, only what is wrong with the vehicle.

These Bluetooth dongles can be used on multiple vehicles and the manufacturer support libraries are expanding rapidly.

Please PM me if you would like to discuss. I believe this may make diagnosis of your issue much more efficient.

 

Did not know a modern scanner that will read the BCM is available reasonably priced.......I was thinking a $1500 Snap On unit with downloadable modules for over a hundred bucks each. I'll look into the Bluetooth to cell phone setup. There is a young guy who owns a small shop close by that can read the codes with his expensive scanner for $50 bucks. He will furnish a readout with all the codes he finds......I've used him before and was able to fix the seatbelt warning on my old Hyundai. I ended up buying a seatbelt bypass thingey for $80 bucks to turn off the annoying check engine light. The seatbelt warning still works but u can't put a person less than 70 pounds in the front passenger seat because the airbag might activate and decapitate a small person! Getting that thought out of my head and back to my boy's Aura, I bet I will still need a wiring diagram though. Going to have a busy weekend. Thanks again my friend

 

I found this for a 2007 Aura. No idea if it is identical. However it does illustrate how the system is constructed and functions.

2007 door lock schematic


The door locks are controlled by the BCM. If you look at each switch, one of the positions directly connects the signal to ground while the other adds a resistance in series with the circuit. I believe the voltage sensed at the BCM determines whether it sends a lock or unlock signal to the latch. There does not appear to be a separate actuator inside the door. Same thing with the passenger side but the resistance value is different.

As for the trunk latch, I'm thinking it is a similar setup but I have not yet found the schematic