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217K views 392 replies 93 participants last post by  Bucketokarma 
#1 ·
I purchased my 2008 CTS at the end of October and while it did not have Bluetooth, it had all the other options I was looking for.

My 2008 was manufactured in March 08 and therefore has Gen 7 OnStar hardware.

I wanted to see if it was possible to add Bluetooth to the vehicle, without using aftermarket parts. I figured if I wasn't able to do it through the OnStar module, I'd buy a hands-free visor-mount Bluetooth speakerphone instead.

I bought a salvaged unit off eBay for $65 that came from a 2009 CTS. I found the device from Nordstrom's Automotive and is identified by
CADILLAC CTS 2009 Communication; (OnStar, opt UE1), w/voice recognition (opt UPF).
The model # is 25990227.

Before purchasing, I obtained a copy of the service manual and found that there weren’t any wiring changes that could cause a short or irreparable damage to both the module and my vehicle. I figured if the gen 8 module didn't work, I'd probably could plug the gen 7 module back in without problems.

I know that there was information about the new Bluetooth wiring provisions (WXS) when the Gen 8 Module was introduced. My guess is these wires were already part of the existing Nav system wiring (UQA, UQS), and were just separated into a separate wiring scheme in 2009 vehicles to allow Non-Nav cars to support Bluetooth as well (However, my guess is non-Nav cars might have this wiring too as OnStar runs through the stereo..... just don't take my word for it.) They provide a "Remote Playback Device Left Audio Signal", Mute, Ground and a "Cellular Microphone Signal" to the Nav System.
As mentioned, either my car already has it, or it's not needed as my Nav mutes when a call comes in, and I can hear the caller (and they can hear me) clearly when using Bluetooth.


The device arrived on Friday looks almost identical to the Gen 7 module. The only difference is it has a Bluetooth Connector / Antenna, as well as a Bluetooth logo and MAC address on the label.
Took me about an hour to remove the back seat, interior trim and rear shelf (as well as disable the airbags). At this point I had access to the module. I plugged the new one and turned on the car. Success! I went into the Hands-Free menu and said “Bluetooth” and it recognized it! I paired my phone and was able to make calls through the stereo. At this point my OnStar light was red, but probably because the device wasn’t connected long enough to get an OnStar and GPS signal.

Unfortunately, it took me 4 HOURS to remove the old module. Why? The old module is mounted to a plate and when I tried to loosen the nut holding down the module, the bolt turned as well.

I was unable to remove the tray as it was bolted down and one of the bolts had cap on it that couldn’t be removed (it had a wiring harness running through it, so I was unable to unscrew it).

I had to resort to taping a wrench to a paint stick and sliding it under the try to grab hold of the bolt. (There is a hole almost underneath the module in the trunk; however it was not large enough to place an object in to prevent the bolt from turning).

Anyways, although it took over 5 hours to do, I’m happy that it was successful. I will admit though I’m not sure if it’s a 100% success as there were a few problems that I outlined below:

Quirks

After installing the module and getting it mounted in the back of my vehicle, I turned my car onto accessory mode to verify the module worked before putting the car back together.
  • While the car was on accessory mode, my dash and Nav "restarted" and the DIC came up with the message "Stabilitrack Off". This is a total guess, but I wonder if it was due to the car detecting the new module, OR the battery was almost dead as I was in/out of the car for over 6 hours without starting it. To be safe I charged the battery overnight and it hasn't happened since.
  • Also, on Sunday morning, my NAV display came up with the error that "the display unit is too hot and will shut down". This message disappeared after a few seconds and the Nav display is working fine.
I installed the module on Saturday and I haven't had any problems with the car since. Now I know that was only two days ago, but if I see anything else occur, I’ll post about it.


Unresolved Questions / Issues
  • When I have an incoming call, the Caller ID on the DIC shows "UNAVAILABLE". However, this may be due to the Bluetooth capabilities of the cell phone.
  • Also, as this is a used module, I'm not sure if OnStar will be willing to reset the programming on the device to match my vehicle. Therefore, I don't know if I will be able to activate OnStar services on the vehicle. The good news is the OnStar light is green. I might look into it if I decide to activate OnStar in the New Year. There is a guy on the Silverado forums who said he called up OnStar and they downloaded the updated information about his car to the module. However, I'm unsure if he had a new, or a used module.
Of course I can’t make any guarantees if will work in your car (As I said my car has Nav and was manufactured in March 08. Also, I don’t have THAT much experience with electrical or automotive systems, I’m an IT guy) but hey if you’re looking for a way to add Bluetooth to your 08, this MIGHT be a way to do it.
 
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#136 · (Edited)
I was just looking over the Cadillac site to see if the 2010 base model still came with leatherette seats and noticed that the base sedan does not come with "Bluetooth", seems odd that it would not be part of the On* bundle.
From the Cadillac list of model comparisons
"Trim Specific Features
Please note features to the right may be in addition to, or in place of, features in other trims.

3.0L V6 (RWD)

Bluetooth® Connectivity9 Not Available"
 
#137 ·
So, the mod worked great. As noted, the only issue is that the box doesn't connect to OnStar. I am trying to figure out whether my box is one of the ones that falls under the recall. My box was sourced from AutoCraft Electronics, which is the outfit that GM dealers are supposed to go through for new OnStar boxes. Anyone know which serial numbers it applies to?
 
#141 ·
Well thanks to Gram, Roger, and CSalmon! I installed the 8.1 Onstar module (purchased from Roger, Canada) on Saturday. Hardest part of the install was unplugging the blue and purple connectors without breaking them. I was easily able to get the tray off using a 1/4" ratchet and 9mm socket (I believe). For an update, my tray had 3 nuts in the front and one in the back as well as the bolt and nut in back as well. I did not need to fashion a wrench to a paint stick as the bolt did not turn with the nut, after breaking everything loose with the socket, I used my hands to remove.

This morning I took the car to Allen Cadillac in Laguna Niguel, Ca and they did the Onstar setup in 30 minutes or so. They charged $53 (which I gladly paid). I called Onstar on my way to work using the Onstar call button and ten minutes late my car was associated with 8.1! This makes the car a 9.5 out of 10 in my book. Up from a 7.5 (not coming with BT). That's just my opinion anyways. I would definitely recommend this upgrade to anyone lacking BT!

Thanks again!
 
#143 ·
Scout,

This may be a stupid question, but you did take your car to the dealership and have them perform the Onstar setup right? Mine didn't connect either, all I had was a red light until they did the setup. I'm sorry that yours didn't fully work... at least you have bluetooth though! That's all I ever cared about.
 
#144 ·
Matt, glad to hear it all worked out!

One quick question: Does the Caller ID appear with your incoming OnStar and Bluetooth calls, or does it say "UNAVAILABLE?"

Scout, Have you tried contacting Nordstroms Automotive? Maybe they can source them from a salvaged vehicles if you provide them with the two part #s
 
#146 ·
Yes it does Gram, also yesterday the radio even started to announce the number of the person calling. Perhaps it always will do this, but I answer it before it has the chance. But overall, yes it displays the number. Unfortunately I have an iPhone 3G (for now) which does not support stored voice calling, so to make a call handsfree I have to know everyone's number (that or use my phone to call, which I gladly do).
 
#148 ·
Interesting. Agreif your car also has the 8.0 module correct? hmm Maybe I can ask Onstar about it.

Everything else appears on the DIC, (Dialed Numbers, Minutes, "Connecting to OnStar"), however incoming calls appear as "UNKNOWN".

I originally though it was due to my phone (Blackberry 8900.... which I would expect to support Caller ID over Bluetooth), but when I activated OnStar, I found it was happenining to incoming OnStar calls too.
 
#150 ·
Gramzter, understand that you installed the gen 8.0 unit (25990227) correct? Have you experienced any of the problems that have been documented with gen 8.0 and led to the release of the 8.1 unit (20787642)? Reason I ask is that I have bought a gen 8.0 unit myself to put in my March 08 CTS (missed bluetooth by 3 weeks!) and am ready to install, but want to know if I should keep looking for a gen 8.1 unit, approach my dealer to try to get the 8.0 upgraded to 8.1 through the recall program, or just go ahead regardless and hope for the best.

Thanks by the way for the original groundwork on this project and excellent install guidance. (In advance of the install, I have drilled a small hole in the rear deck under the bolt in question so I can get a socket on it if necessary - seemed like a prudent investment of 5 minutes!)
 
#152 ·
Gramzter, understand that you installed the gen 8.0 unit (25990227) correct? Have you experienced any of the problems that have been documented with gen 8.0 and led to the release of the 8.1 unit (20787642)? Reason I ask is that I have bought a gen 8.0 unit myself to put in my March 08 CTS (missed bluetooth by 3 weeks!) and am ready to install, but want to know if I should keep looking for a gen 8.1 unit, approach my dealer to try to get the 8.0 upgraded to 8.1 through the recall program, or just go ahead regardless and hope for the best.

Thanks by the way for the original groundwork on this project and excellent install guidance. (In advance of the install, I have drilled a small hole in the rear deck under the bolt in question so I can get a socket on it if necessary - seemed like a prudent investment of 5 minutes!)
You're welcome Ed!

Sounds like we were in the same boat. Although I purchased my car back in October, my car was made 3/28/2008.

Aside from my caller ID not working (which may be due something else...agreif says his works), the module has been working great. Everything displays on the DIC properly, my OnStar LED has been solid green* and I've used OnStar a few times and haven't had any problems. I also get my monthly diagnostic reports.

Although the 8.0 module was part of the recall, after doing some investigation, I don't think the entire batch is affected.
Take a look a link at this over at the Corvette Forum: http://forums.corvetteforum.com/1572976141

You'll notice the Station ID's of the modules affected by the recall. However, I don't think 100% of the modules listed are affected.

My module is listed within the Affected Unit STID Range, but works great. My bet is that the ranges listed have a higher % of affected units (but probably still have units that are okay, like mine).

The only way to find out is to try it out. You can quickly find out if you connect the unit and press the onstar button. If it connects to OnStar (you don't even have to reach an advisor, just hear the "music on hold"), you should be okay. Affected units have a problem where they will continuously "beep" (indicating it's trying to call Onstar... just like normal units), but the call never gets made.

*I did have a problem with my Bluetooth Antenna, but as mentioned, this is independant of the OnStar module and is not on a parts restriction. I was getting a periodic red OnStar LED. I Called OnStar, they told me the problem was with the bluetooth antenna, I purchased a replacement and it's been green ever since.
 
#151 ·
Scout, nice sarcasim. You are making me feel bad (sarcasim too) - maybe you needed a little more patience or could have sent a second PM or even posted on the forum like Matt.

I tried to answered your PM - maybe unsuccessfully, and I checked online (this forum) to post back to you, but you had already purchased one somewthere else, so I sold it to Matt - otherwise I would have sold it to you. I only reposted that I still had mine after you posted that you already picked one up. I just wanted to mention that was only a couple of days between your original PM and me checking the forum. On the other hand Matt was quite easy to get along with by email so it worked out anyway.

I just checked for another one at the junk yard where I got mine from and from the other junk yard that had one while I was searching for one. Neither have one - if they had I would send it to you.

Oh well. Good luck.
 
#155 · (Edited)
Yeah, I know. I'm a jerk for offering to buy your item.


To EdGrimley:

Beware of the 8.0 box. While Gramzster has a good one, I got a defective one, which is funny because it was actually sold through AutoCraft Electronics to a middleman as a replacement. Mine is within the affected StID range and exhibits all the symptoms (i.e. the light is green but the box cannot contact onstar). It attempts to contact, but can't ever connect.
 
#153 ·
As stated Gram, my caller ID works too. If you need I can post a pic or video of it for your comparison. I have the Onstar 8.1 though if that makes any difference. Tomorrow I am going to see if it announces the call every time. It always shows the caller ID though.

In case I forgot to, I wanted to thank you for all of your ground work as well. This completely made my car! My car was built around the same time as yours; I purchased it last December. I was unaware of the bluetooth discrepancy and am glad that it worked out in the end. Especially for only $200! I had been comparing my car and a black one. I'm not sure when the black one was made, but my mind was quickly made up after seeing my silver CTS. It was the Premium Luxury edition and came with the chrome rims and remote keyless entry. That's the second best thing about my car. Not having to take the keys out of my pocket!

Thanks again!
 
#154 ·
As stated Gram, my caller ID works too. If you need I can post a pic or video of it for your comparison. I have the Onstar 8.1 though if that makes any difference. Tomorrow I am going to see if it announces the call every time. It always shows the caller ID though.

In case I forgot to, I wanted to thank you for all of your ground work as well. This completely made my car! My car was built around the same time as yours; I purchased it last December. I was unaware of the bluetooth discrepancy and am glad that it worked out in the end. Especially for only $200! I had been comparing my car and a black one. I'm not sure when the black one was made, but my mind was quickly made up after seeing my silver CTS. It was the Premium Luxury edition and came with the chrome rims and remote keyless entry. That's the second best thing about my car. Not having to take the keys out of my pocket!

Thanks again!
Glad to have Helped (thanks to csalmon and ewill3rd as well!).

It's been an interesting project aswhen doing this, it was pretty much a shot in the dark. However, as I looked at the service documents, I realized there was a chance this would work..... It was quite a surprise to find out it was pretty much plug-and-play (aside from the OnStar configuration).

Thanks for letting me know about your 8.1. I figured it was something that affected the 8.0 modules, but now I realize it's probably something related to the configuration of mine. No Biggie.
 
#158 ·
OK - just finished switchover made from gen 7.0 to gen 8.0 unit and accomplished in just 45 minutes! I had predrilled a 1 inch hole under the deck to prepare for the possibility of the unreachable nut problem and I'm glad I did, as it would have been a problem, but with access from underneath it was a snap.

Seems to be working fine, although have not had it flashed to my VIN yet obviously. I may not as I never used Onstar except for the phone. Paired it with my iphone no problem. Previous owner was obviously using it as his phones are still in memory.

Will be watching carefully for problems noted in TSB, but not all gen 8.0 units are problematic.

Just happy to have Bluetooth for now.
 
#159 ·
Seems to be working fine, although have not had it flashed to my VIN yet obviously. I may not as I never used Onstar except for the phone. Paired it with my iphone no problem. Previous owner was obviously using it as his phones are still in memory.
As a suggestion, I think getting it flashed cost me $50 and 1 hour. If you have a dealership willing to do it (if you live in SoCal, try Allen Cadillac) I would suggest shelling out the cash. In that case, if you ever decide to sell, you don't need to tell the prospective buyer that it is linked to another car. Something like that may scare off some buyers. Just my opinion. I'm glad everything worked for you as well! Thanks again to everyone that's done this before us as it certainly made me LOVE my CTS!
 
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