[Marcus_Halberstram]

Hi all!, So I am having this problem for the second time in just a two years on my 2008 CTS with remote keyless entry. The front driver side door will not actuate. In order to open the door I have to insert the key. Needless to say this is beyond frustrating and people are starting to wonder why my door handle of all things never seems to work. Passenger side works fine and the back doors unlock and lock remotely with no problem. There was no intermittent issues with this, it simply worked fine one day and then stopped working overnight with no warning.

Before I look into having the actuator replaced (again) or the microswitches, I am wondering if it could be a bad relay or some other simple fix. I looked at the fuse box maps and can only see a "Passenger door module" relay in the trunk fuse box. Does anyone happen to know which relay would be the culprit here? Or if there are any other easy fixes I can try before I start pulling door panels or throwing parts at it? Any advice would be very much appreciated!

Also Just a note to Cadillac Canada here: I payed Mcnaught Cadillac Buick GMC in Winnipeg over $300 to have this exact same issue repaired on the same door barely 2 years ago which was of course not covered by the extended warranty I was sold. I understand this is an older vehicle but it barely has 115,000km on it (71k miles!) and the components were replaced barely 2 years ago. I hate to say this, because I love Cadillacs *(this is my second) but i'm not sure i will ever feel comfortable buying another one with these kinds of parts quality issues on a system that should not fail every two years. You would think Cadillac Canada wouldn't wish to forfeit the customer lifetime value of a loyal customer over a door handle! But I digress.

Thanks again CF.

 

[TheFlash]

Check with your Cadillac dealer, but my Cadillac dealer here in Las Vegas grantees parts and labor for TWO years.

 

[Coneill]

Hi all!, So I am having this problem for the second time in just a two years on my 2008 CTS with remote keyless entry. The front driver side door will not actuate. In order to open the door I have to insert the key. Needless to say this is beyond frustrating and people are starting to wonder why my door handle of all things never seems to work. Passenger side works fine and the back doors unlock and lock remotely with no problem. There was no intermittent issues with this, it simply worked fine one day and then stopped working overnight with no warning.

Before I look into having the actuator replaced (again) or the microswitches, I am wondering if it could be a bad relay or some other simple fix. I looked at the fuse box maps and can only see a "Passenger door module" relay in the trunk fuse box. Does anyone happen to know which relay would be the culprit here? Or if there are any other easy fixes I can try before I start pulling door panels or throwing parts at it? Any advice would be very much appreciated!

Also Just a note to Cadillac Canada here: I payed Mcnaught Cadillac Buick GMC in Winnipeg over $300 to have this exact same issue repaired on the same door barely 2 years ago which was of course not covered by the extended warranty I was sold. I understand this is an older vehicle but it barely has 115,000km on it (71k miles!) and the components were replaced barely 2 years ago. I hate to say this, because I love Cadillacs *(this is my second) but i'm not sure i will ever feel comfortable buying another one with these kinds of parts quality issues on a system that should not fail every two years. You would think Cadillac Canada wouldn't wish to forfeit the customer lifetime value of a loyal customer over a door handle! But I digress.

Thanks again CF.

 

[Joseph Upson]

Sounds like it's time for you to source the wiring diagrams and trace the output/input wires responsible for this function end to end. Once you have done that it should be pretty simple to determine where the command signal begins and ends, if it is present at all. The body control module has to be in the loop so that might be the best place to start as far as looking at wiring diagrams are concerned. Once the multimeter is connected at each break point, it should be as simple as pressing the remote button and looking for the momentary voltage spike. The problem might be the door control module, it's a lot more complicated than just being a little contact switch.

It's easy to blame the car, but understand there are potential complications that go along with the kind of complexity that you appreciate in the car. Any vehicle you purchase with the kind of technology this car has, is subject to the kind of problem you're experiencing. Why should you care that others are worried about your door handle.

 

[Joseph Upson]

Bad deal sorry, i hear your health car system is not very good up there either. A lot of Canadians come down to the hospital my wife's works at in Duluth and the one her mom works at in Bemidji. Maybe you need to take your car down here too to a Cadillac/gm dealership.

That sure came out of nowhere.

 

[Coneill]

I'll stop my rants. Thanks for pointing it out

 

[Long]

Ha! We almost never go off on tangents here in the second gen forum.

Marcus_Halberstram, I completely understand your feeling of frustration regarding this issue.
Everybody loves the bells & whistles...until they stop working. I much prefer the traditional key fob and door handle system on my Tahoe, but it's a Chevy, not a Cadillac.
This is a part that is based on use, not mileage. Consider how many times in the last two years you've opened that driver door on your CTS. If you have some basic DIY skills, you can do this repair yourself in an afternoon and save yourself roughly 60% of what the dealer charged you.

 

[Joseph Upson]

...This is a part that is based on use, not mileage...

I'm trying to avoid an encounter with this issue to the extent that I don't shut the door when I refuel.

 

[Long]

I'm trying to avoid an encounter with this issue to the extent that I don't shut the door when I refuel.

You're not alone. My Tahoe has articulated running boards and I do the same thing and even open doors for passengers to avoid multiple deployments for a single ingress or egress.
They believe I'm being chivalrous...

 

[Marcus_Halberstram]

This is a part that is based on use, not mileage. Consider how many times in the last two years you've opened that driver door on your CTS. I

That's fair. I honestly don't use the car very much, probably 2-3 times a week. I dont think a system like this should need servicing every two years but anways.

If you have some basic DIY skills, you can do this repair yourself in an afternoon and save yourself roughly 60% of what the dealer charged you.

To wit, i'd like to start by ruling out the simple things before i pull the door panel and dig out the multimeter in minus 20 celcius lol. For the life of me I can't locate which relay(s) controls this system. Does anyone know which relay this would be? or if this is even a possible cause at all? thanks!

 

[Joseph Upson]

I'm guessing there is no relay. A fuse might be possible, but the technology is such that some of the circuitry is load managed and when it malfunctions a code is set and the particular function disabled. Window indexing is a perfect example. My driver window was rolled down following a previous battery disconnect and it would not roll up. It could not be commanded to roll up using a scan tool with bidirectional function either, although I could hear a faint motor noise during attempts. Upon applying the 5 second window indexing procedure, normal function was restored. So as I mentioned earlier, the problem could be the door control module, the little panel that looks like simple switches that controls all four windows that is actually a sophisticated collection of circuits and electronics.

No doubt there's a BCM code stored associated with the problem that you're having that will give you some insight if you can acquire it with a scan tool.

 

[Marcus_Halberstram]

I'm guessing there is no relay. A fuse might be possible, but the technology is such that some of the circuitry is load managed and when it malfunctions a code is set and the particular function disabled. Window indexing is a perfect example. My driver window was rolled down following a previous battery disconnect and it would not roll up. It could not be commanded to roll up using a scan tool with bidirectional function either, although I could hear a faint motor noise during attempts. Upon applying the 5 second window indexing procedure, normal function was restored. So as I mentioned earlier, the problem could be the door control module, the little panel that looks like simple switches that controls all four windows that is actually a sophisticated collection of circuits and electronics.

No doubt there's a BCM code stored associated with the problem that you're having that will give you some insight if you can acquire it with a scan tool.

Thanks for explaining Joseph! That gives me some leads to go on. Il see if i can get my hands on a scantool that does BCM. Would a malfunctioning door control module be ruled out if the other controls on the door panel are functioning no?

 

[Joseph Upson]

Thanks for explaining Joseph! That gives me some leads to go on. Il see if i can get my hands on a scantool that does BCM. Would a malfunctioning door control module be ruled out if the other controls on the door panel are functioning no?

Unfortunately no regarding the question. When my window would not roll up, I did what you are doing now, troubleshoot blind as far as information is concerned. That lead me to remove the module and disassemble it a bit looking for a possible problem with a contact point in the switch. That's how I discovered it's loaded with electronics, like a mini computer. I put it back together with fear and trembling hoping that I did not add to my troubles by opening it. I believe it also has some control over cabin lighting as well regarding recent info I looked up regarding the subject in another thread.

If the actuator is the problem, there will be a code stored, as well as for an open, or grounded circuit. My passenger side mirror does not work and although there is no control for it on the passenger door module, the code referencing the malfunction mentions "Passenger door switch" and states the horizontal circuit is open. I'm not sure if the motor is bad, or there's a problem with the switch, or if the circuit really is open, but I have a code to look up for diagnostic purposes when I decide to correct it.

 

[Long]

In my case, my scanner gave me B3849 which was a failed microswitch assembly.

 

[rc135tx]

I had a very similar problem with my '08 CTS. The dealer did a lot of stuff that never resolved the problem. To make a long story a bit shorter, I replaced the vehicle's battery. Maybe short on logic, but it fixed the problem & it never returned.

 

[Joseph Upson]

I had a very similar problem with my '08 CTS. The dealer did a lot of stuff that never resolved the problem. To make a long story a bit shorter, I replaced the vehicle's battery. Maybe short on logic, but it fixed the problem & it never returned.

Low voltage/current to electric motors generates additional and potentially part damaging heat long term, due to the sustained load necessary to complete the cycle. Imagine the strain on a starter lugging a motor over several additional revs before the motor finally catches and runs, due to a weak battery for example. I usually remote start first to insure a good power zap when the handle is pulled.