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2006 STS V6
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46 Posts
Discussion Starter · #1 · (Edited)
Thanks to all prior member posts about the micro switches or the door handle antenna, however, I'm still confused about the troubleshooting steps. There was a detailed matrix posted by one really smart member, but that goes over my head. I'm not that tech savvy.

Is there anyone who can post a step by step procedure to test out the remote keyless entry problem?

My issue is like many others. At first, I noticed that pulling the door handle did not open the door. I can open it with the door key. I put a new battery in the key fob. No change. The 2nd key fob also behaves the same. Strangely, the issue seemed intermittent, but then became permanent.

The passenger door opens without the key. The keyless system seems to work fine on passenger side.

Like probably many unsophisticated readers of this forum, I don't see a definitive "how to" diagnose the Door Antenna Issue vs. Microswitch problems (realizing that there could be other issues also).

If there is someone who can explain the troubleshooting in plain English, it would be greatly appreciated.

Sincerely,

AR
 

· Registered
2008 STS-V, 2008 STS AWD
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439 Posts
First, remove the inside door trim, it doesn't need to be completely removed just enough to gain access to the upper rear door area. Separate the black plastic water shield from the upper rear area to gain access to the door handle electrical connector. There's a six pin connector at the upper rear of the door that's held there with a plastic pin through the sheet metal; unplug the connector's two parts. Using an ohmmeter check the pins on the connector half that is connected to the outside door handle.
The YELLOW and WHITE wires go to the outside door handle antenna, connect the ohmmeter to those pins; the reading should be low but not high or shorted, 10-20 ohms is around what to expect. Move the outside handle to the fully open position, the reading should be constant.
Next check the first of two micro switches, connect the ohmmeter to the GRAY and GREEN wire pins. The reading with the outside handle untouched should be infinity, an open contact. Slowly open the outside door handle, the reading should change to near zero ohms, a closed contact. Measure about how far the handle is open when this happens. Continue to open the outside door handle until fully opened, the reading should remain the same, a closed contact. Release the outside handle, the reading should revert back to infinity, an open contact.
Next check the second micro switch, connect the ohmmeter to the ORANGE and BLUE wire pins. With the outside door handle untouched the reading should be infinity, an open contact. Slowly open the outside door handle, the reading should change to near zero ohms, a closed contact. Measure about how far the handle is opened when this happens. Continue to open the outside handle until fully opened, the reading should remain the same, a closed contact. Release the outside handle, the reading should revert back to infinity, an open cointact.
Compare the distance measurments taken if the switches worked, the second switch should close after the first switch as the outside door handle is opened. If either micro switch is bad from the above test you can order a replacement inner door handle or replace the faulty micro switch(s) on the one you have now. I ordered new micro switches using part numbers from an old post (ZD30S20A01), the new switches were similar but slightly larger making them very difficult to install. The old micro switches are potted into the inner door handle so the potting has to be removed with a Dremel or similar tool then the new correct micro switches need to be soldered to the correct wires the old micro switches were connected to. Additional short lenghts of wire need to be added to the old wires if they were shortened in the potting removal. If the handle antenna is bad that needs to be replaced. I did this fix a few weeks ago and found one good micro switch, one bad micro switch and a good antenna. After replacing both micro switches (due to the potting removal it's faster to do both) the door operates like new. There were a few days recently where the door didn't open right but that was caused by a bad contact in the FOB, cleaning the battery contacts corrected it.
The outside door handle has no mechanical connection to the door latch, only the inside door handle connects to the latch with a cable. When the outside door handle antenna recognizes the FOB it then tells the system to allow the micro switch commands. As the outside handle is opened, a molded cam in the handle closes the first micro switch and then the second. Once the system receives this information a motor in the door latch releases the door, that's why there's a short delay when the outside door handle is pulled but not the inside door handle.
In addition to the outside door handle, the door latch has three micro switches, a motor and a lot of parts inside. I switched door latches and the in the door control box from a working car but it was the one bad micro switch in the outside door handle that caused the problem.
 

· Registered
Cadillac STS 3.6 2006
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85 Posts
I had a similar problem to you, I had to change the 2 microswits in the handle.
There is a thread in which there is a diagram of how the red diode in the door should flash, showing the problem.
Since I am a Dane I am not so good at searching because I am not sure of the right English words, but if you are looking for yourself, you will surely find a .jpg image that explains what the flashes that come from the diode when you take the handle means.
With me it was both microswits that had to be changed and it was actually not difficult if you follow part 1 and 2 in the link I have attached as another Cadillac driver has made.
I hope you understand what I mean.
greetings from Denmark
Stig
https://www.cadillacforums.com/foru...rivers-door-micro-switch-replacement-how.html
 

· Registered
2006 STS V6
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46 Posts
Discussion Starter · #4 ·
Unfortunately, my problem still exist. Though it intermittently works fine for a few days. When it does not work I believe there is no red LED light that flashes when I attempt to open the door. Not sure if the other doors unlock when I pull the handle. I was going to test it, but lo and behold it’s working fine now....for now!

Is there anything I should attempt to inspect inside the door panel? Bear in mind I am mechanically challenged. I can take off the door panel though. Anything electrical or testing same is not my forte.

Is there anything I should lubricate? If it’s really the micro switches or the antenna going bad, I assume there is no point in lubricant. If yes to lube what kind? WD40?

Does rain make a difference? It’s lightly raining now and the system is working. But earlier today the system was not working. It was not raining then.

Let’s assume it stops working again. Safe bet. How do I know whether it is the micro switch or the antenna? Or possibly the latch release? Help me trouble shoot this please.

Approach with key fob....pull handle. No LED. No door open/unlatch. Other doors unlock. Equals?

Unlock with remote on key fob. Approach. Pull handle. No LED. No open/unlatch. Equals?

Can always open/unlatch with the physical key. And passenger side always works.

Please help me narrow this down. Thanks much.

AR
 

· Registered
2008 STS-V, 2008 STS AWD
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439 Posts
Have you tried another FOB? Poor internal FOB contacts will cause intermittent operation? If an inner door handle microswitch is bad, spraying WD40 won't correct it and neither will rain. If you can't trouble shoot using the above directions can you change the inner door handle or handle antenna? If not then take it to a dealer and be done with it. If you can then start with a new inner door handle assembly but try another FOB first if you haven't already.
 

· Registered
2006 STS V6
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46 Posts
Discussion Starter · #6 ·
I'm currently having no problems. It started to work again.

I have a OBDII scanner made by BlueDriver. I'm not sure, but I used it to read for codes and then clear codes and it does a deep dive on codes. There were some codes for loss of contact with the radio which I've noticed before. Doubting that clearing the codes caused a KeyFob reading problem. But maybe.

I did change the battery in the fob. Assuming that there is not a reprogramming required for a simple battery swap.

Both my fobs were not working with the door unlock feature. But since yesterday, they both are working.

This was only the driver door Passenger works fine.

Also, I did replace the window control switches on the driver side about 5 weeks ago. But there was not fob/door problem until weeks later.

But, it's working now. So I am at a loss to explain that. If I had to hazard a diagnosis it would be micro switches as I believe the system is sensing the proximity of the fob, but not allowing the latch to open the door. I believe the LED light goes on signaling that the antenna is working and receiving the fob signal. But, that's my recollection. I can't test it now as it is working as intended now.

Is there any logic to resetting the computer module (not sure which one) that might cause a temporary malfunction? Or, as i read in one post, a member had his mechanic reset the computer module (again, not sure which one) and the lock started working correctly again.

It's a confusing system for sure. If it is the micro switches, I might try to tackle replacing them myself. I'll have to study the "how to" posts in the forum first.

AR
 

· Registered
2005 STS V8 AWD
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22 Posts
When my intermittent door handle acts up I shoot the inside of the key lock with CRC electrical cleaner. (I'm assuming it eventually makes it's way to the switches) I shoot a liberal amount in there with the straw attachment. I place a blue shop towel right below the lock, but it appears that it does not hurt the finish. I work the handle back and lightly contorting the angle of pull. I then follow that up with a liberal amount of liquid wrench deep penetrating oil followed by another minute of working the handle. My handle had stopped working for about 6 months before I tried this. I bought the micro-switches and was about to swap them out, I had nothing to lose. This was 2 years ago and acts up every once in a while.

https://www.autozone.com/miscellane...rts-cleaner/crc-electronic-cleaner/128435_0_0
https://www.walmart.com/ip/LIQUID-W...6816124?wmlspartner=wlpa&selectedSellerId=282
 

· Registered
2006 STS V6
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46 Posts
Discussion Starter · #8 ·
I like your idea. I too tried to spray liquid wrench into the keyhole as well as into the areas behind the door handle. Also, sprayed it on the latch mechanism. Using the extension straw I tried to insert it into the areas where there was an opening. Seemed to help. I haven't had a lock out since.

There was one day I thought it had stopped working, but I held the handle out and after about 3 or 4 seconds the door opened. Then it started working consistently again.

Whether this is a band aid or not, I don't know. But, it worked. Coincidence? Maybe. I plan on removing the door panel and inspecting the whole mechanism and switches if it stops again. But for now, it works again!!

Crazy how intermittent it is. When it doesn't work and I approach the car that is locked, the LED light is definitely OFF. But if I hold the handle out, the rear doors will unlock. If I unlock the doors with the key fob and pull the handle, still no light. So using the chart/matrix from another post, it seems that I have micro switch failure. But the intermittent nature is bizarre.

But that is all when it's not working and right now it's all working!!
 

· Registered
2006 STS V6
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46 Posts
Discussion Starter · #10 ·
What is the relay click? When mine is not working I don’t get the red LED and I don’t hear anything like a click. If I hold the handle out the other locks will unlock. The door won’t open though.
 

· Registered
2008 STS-V, 2008 STS AWD
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439 Posts
The next time the door doesn't open, take the FOB out of your pocket and push the unlock and then the lock buttons to see if the FOB is communicating with the car. If the doors don't lock and unlock the problem isn't the doors it's the FOB. If the doors unlock and lock then the FOB is OK. I had a problem with the FOB where one set of battery contacts was intermittent, the door sometimes wouldn't open and the FOB wouldn't lock or unlock the doors. Inside the FOB one set of battery contacts was stronger than the other set sometimes resulting in no battery power and no door opening.
 
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