Hello all,
I am an new XLR owner. Had a 2004 CTS. Loved it and really love the XLR.
2006 silver with black interior. Wife has a 2005 yellow convertible Corvette.
When i bought the XLR it had a Kenwood DNX5120 radio/nav installed but it is not hooked up to the retained access power (RAP) and turns off as soon as i turn the car off.
I asked the Caddy dealer and they told me it could not be hooked up because RAP power was supplied through a "class II data com link".
There has to be a way. I have seen several posts for new radios installed.
Which wire(s) do I need to hook the radio power up to.
Help and thanks,
Jeff

Welcome to the XLR Forum!!

There are several owners here that have installed other radio/nav systems. If one of them doesn't respond shortly, perhaps you could access the online instruction sheets for Pioneer and some of the others to see how the power hook ups are configured.


Regards

I hate my factory radio and would love to have it replaced or upgraded. Can those who have had this done, post some pics? Give details as to what was done? Who did it? Likes? Dislikes? What was lost (i.e steering wheel controls, onstar, etc.)? I was thinking of leaving the seat and dash speakers alone, adding components in the stock door locations and slim subs behind the seats. Any thoughts? Before anyone asks, I'm only 5'7" and don't move the seats all the way back.

Thanks,
Dom

Dom:

When you get a chance look at the Pioneer NAV/Radio/Backup Camera system that many of the high end customizers are installing and swappping out with the stock systems.

I think it is on their online site.

I found these model numbers in the older postings:

PIONEER AVIC Z2

KENWOOD DNX 5120 AND DNX 8120

Greetings Jeff!

First off, welcome to the forum!

Power is supplied to the entertainment system across multiple paths from the Body Control Module (BCM.) The entertainment system consists of multiple modules (Radio, Amplifiers, CD Changer, Satellite receiver) linked by the Class 2 serial buss.

For the Radio, Fuse 17's (RADIO/ANT/VCS) output in the BCM goes to Connector C1 (the largest of the three on the radio, with 32 pins) pin F1, which is a Red/White wire on the bottom left corner (referenced with the connector clip on top.) Ground (E16) is the Black and White wire on the top/right.

Just to add a little more clarity if this doesn't make sense, the connector face is arranged like this:

E1 X X X X X X X X X X X X X X E16
F1 X X X X X X X X X X X X X X F16

The power is described as Battery Positive Voltage and I don't see any relays in the BCM supply, so it should be always hot. This may not be what you want. The stock radio is firmware-controlled. When the vehicle is powered up, the Class 2 buss sends out the VIN. If it doesn't match the VIN stored in the radio's memory, the radio won't operate.

Switched power (from the Aux Power Relay) was discussed in an earlier post about a month ago. Basically, the Aux Power Outlet (below the center armrest) is on a 20A fused (AUX POWER) line supplied by the Auxilliary Power relay.

Unless your new entertainment system has a way of communicating across the Class 2 bus, you may lose the operability of the steering wheel-mounted switches and interface to the HUD.

I hope this is of some help to you. If not, let us know and someone will have the answer you need.

CC :seeya

Sorry Jeff. I should have responded to your post before my rant. CC's definition is def. going to be more involved than mine, but here goes. I am pretty familiar with car audio circuitry. I don't know if my opinion applies to the xlr, but on MOST other GM's, the switched power lead to radio automatically remained hot until a door was opened or it timed out. This was EXTERNAL and NOT built in to the radio circuitry, so swapping units would have no effect on the retained power on a new head unit. In the older GM's this was a the yellow wire on the radio wiring harness. It might be different on the XLR.

This is really a cool site.
So many things I want to do and buy. Wind-resistor with Caddy emblem is top of the list.

Thank you all very much for the info but did not work.
I do not want to hook the radio up to a full time hot. Both the cigarette lighter ports and F1 are hot even after the door is opened.

It is the yellow wire providing power to the radio but it looses power as soon as the ingnition is turned off.
I am baffeled? Because I agree this is not a radio issue, it is the car wiring. Why hot with a factory radio in RAP but not with an aftermarket radio.
Someone has done this. Please help and thanks.
I freaking love this car.
FYI for the age folks, I am 43.

Jeff,

BTW. What does the system look like in dash? Speakers? Sub Woofer? Amps?How does it sound?

Dom

RAP (Retained Accessory Power) is provided to the power windows, instrument panel cluster, DIC, and entertainment system. RAP will end when either the BCM detects a opening of a passenger or driver door, the RAP timer completes, the battery voltage drops to a set point or the ignition switch changes state.

The Body Control Module determines the power state of the vehicle and transmits it over the Class 2 network. This explains why the engineers designed the radio power to be always hot. The firmware is the switch. The XLR is a rolling testbed for GM vehicles of the future. While other GM cars employ LANs, XLR takes it a step further. GM discourages adding aftermarket accessories to the electrical system for this reason, and it's one of the first questions asked when performing a diagnostic routine.

Someone on one of the XLR forums installed a new head unit (I think it was an Alpine) into the center console awhile back. If you can locate the thread, they might be able to tell you how they powered it up.

CC :cheers

Hi CC,

The YELLOW wire isn't always hot. It's switched. Jeff, do your windows work after you shut the car off?

Dom

Greetings Dom,

Which yellow wire are you referring to? On the Radio connector (C1) the only yellow wire I see in the service manual is the antenna radio signal on pin E4. Connector C3 Pin 2 has a yellow wire for the VIN request signal (Japanese export models.) The other yellow wires are for the speaker off the amp.

CC :seeya

Hi Again,

Sorry I should have been more clear. I'm certain you are correct. On other GM's the switched power lead for the radio is yellow. I can't be certain about the XLR, I've never looked. Jeff mentioned a yellow wire that was powering the radio so I assumed that was it. Going back to other GM's, the RAP circuit is an external (to the radio) relay. The wire (yellow) will retain power till the door opens or it times out. Now by your logic, the windows shouldn't work either. Correct? I've also read some previous posts regarding the cruise control not working after replacing the radio. Others have had no such problems. It was even mentioned that the stock radio would have to be wired and left in the trunk for the cruise to work? All of this is just too "rocket science", it's just a radio right?

Dom

PS. CC, You are a wealth of knowledge on this forum and I am merely engaging in a technical discussion. I am in no way trying to be sarcastic. Just trying to pick your brain. CHEERS!

"Going back to other GM's, the RAP circuit is an external (to the radio) relay. The wire (yellow) will retain power till the door opens or it times out. Now by your logic, the windows shouldn't work either. Correct?"

Dom,

Just to verify what the books say, (and this explains how it's managed by the XLR) I powered up the car with the Radio on and shut off the ignition, energizing the RAP circuit. Opening the door will instantly shut off the radio, like always. Having read through this post and learned a little about the RAP circuit, we know it's because the Driver Door Module sends a DRIVER DOOR OPEN status over the Class 2 buss to the BCM which shuts off the Radio. With RAP energized, I raised and lowered the driver door window. Then I lowered the window and when it was halfway down, opened the door. As expected, it instantly stopped, courtesy of the RAP circuit. So, while the windows, and entertainment system are operated by switches, their respective module's power is controlled via embedded firmware.

You're right --replacing a car radio isn't rocket science. I've done it many a time -- sometimes while half in the bag, --since my going rate is usually measured in beers. But the XLR is not in the 99% of vehicles that statement pertains to since the entertainment system is integrated with other systems in the vehicle.

As for the DSCC being compromised by an aftermarket radio installation, I can't say I've heard of that, though it's entirely possible if the impedance of the data buss has been altered.

Thanks for the kind words. Whenever I answer a post, I spend time digging through the books to ensure I have my facts straight. I've been guilty of posting how I thought something worked and was wrong, so I try to be as careful as possible before pressing the SEND button. All of us who answer questions are open to criticism (from around the globe, no less!) when we post answers based on opinions or speculation --as we should be. Besides being personally embarrassing, it doesn't help the XLR community a bit. Credibility is the easiest thing to lose and the hardest to earn. But in answering questions, I definately have learned more about this car than had I just spent time reading the books alone. I encourage others to jump in as well with their expertise.

I'm currently writing a series of articles (for lack of a better word) on how to use a Tech 2 with the XLR. What I thought would be a few days of research has turned into much, much, more because I have to decipher the service manuals, record my observations with the Tech 2, then hit the books again to ensure I understand what I've pulled with the Tech 2, and then write it in such a way as to be useful, with examples. My hope is people who want to fix some of the more common problems with this car will feel empowered to do so. We'll see. . .

CC :cheers

The install looks real good. Not factory but real close. I have a very tough eye that sees things a lot of others dont. I think a lot of XLR owners are like that.
I will post some pics soon.

The windows and cruise work fine although I do not like the adaptive cruise version and wish I could turn it off.
The stearing wheel controls work as well. Kenwood sells a special adapter for the steering control. No radio info on the HUD though.
Everthing works fine except the radio turns off as soon as I turn the car off.

Not really sure on the YELLOW power wire. Maybe it was put in with the new radio. It comes from in the dash and provides the 24volts to the radio.

Can I run a power wire from the fuse box circuit that runs the windows?
Is it a 20 amp circuit.

The service manual shows a (always hot) 12 vdc/30 fused (DOOR CONTROLS) red/white wire leaving the I/P Fuse Block supplying power to the Driver Door Module (DDM), FPDM (Front Passenger Door module) and Fuel Door Relay (--Sorry, no acronym for that one.) I don't see where this will give you anything you don't already have Jeff.

CC :cheers

I understand what Jeff is getting at. He wants the RAP. I'm sure you could do this, my only issue would be ENGINE or WINDOW MOTOR NOISE coming through the radio. NOT ADVISED.

Hey CC,
Thanks for hanging in there with me.

I want to tap into the power windows power that is part of the RAP.
I guess it is after the fuse box or module. I am not really sure where to tap into but there is RAP that powers the windows. I want to piggy back onto that wire.
Does that make sense. I am loosing my mind on this.
Thanks,
Jeff

CC,

This has been a great learning thread however I am still a little confused about how the system works so I’m hoping you can share a little more of your knowledge. Is there a wire that runs around the vehicle called RAP that is controlled by the BCM or is RAP simply a firmware state which each module enters (windows and radio included) waiting for a message on the buss to turn themselves off (i.e. radio turns “off” but is still powered) or is it a combination of a RAP circuit for some functions and smart modules for others?

I look forward to reading about your Tech 2 adventures. I have hesitated in buying the service manuals for the XLR because of the fear of discovering that most servicing will require the Tech 2 tool. However after reading this thread, I am going to buy the manuals so that I can follow along better with the conversations.

Thanks,

Jerry

Jerry, you're understanding the RAP circuit as I'm reading it. I've searched for a dedicated RAP (hot line) that de-energizes when the POWER OFF criteria (battery voltage setpoint, door opening, RAP timer expires, or the Ignition Switch changes state) with no such luck. All RAP circuits (entertainment, windows, IPC and DIC displays) interface on the serial buss and are powered from the battery through the BCM. If there's a relay in the BCM that shuts these systems off, I haven't found it. Everything appears to be hardwired hot in the Power Distribution section. Messages like ID verification are passed back and forth across the serial bus between module on power-up; if they don't mach (the radio for instance) they won't power up. This is also under firmware control, so it makes sense that the serial bus can control the RAP function.

In another thread, Carl has his aftermarket stereo head powered by what seems to be the RAP circuit; if so, there has to be a way to do this. He says his stereo shuts down when he opens his door, so it appears that there's a little RAP action going on there.

Yeah, the Tech 2 tutorials are teaching me a lot, but there's a lot of ground to cover to make them meaningful, --like how the manuals are laid out and how different systems interact. A lot of the systems which are pretty straightforward on other vehicles are much more complex with the XLR. (Like the RAP circuit!) The easiest system to understand is the Ultrasonic Rear Parking Assist, since it doesn't interface with anything other than power and your eyeballs. The Tech 2 is defiantely cool though, and I look forward to posting the series in a few weeks. I'll make an offline version using Word with lots of pictures embedded for those folks those who want to take a laptop to the garage and get crazy with it.

And yes, unless you have some kind of super-photographic memory, you'll need the Service Manuals to use the Tech 2. The manuals are well-written and consistent in the way they're organized for each system. Without the Tech 2, you're pretty limited as to what you're able to fix on this car -especially where the top is concerned. As the cars age and XLR techs become scarce, the knowledge in these types of forums will become quite valuable as we share our experiences.

I'll keep my RAP Attack going until I get it figured out or someone else beats me to it.

CC :cheers

Google "RAP circuit GM", it appears there is a module for sale for newer GM cars with Class 2 BUSS. Almost every accessory requires a module to continue working as stock (ONSTAR, BOSE, etc.). There are also some articles online on how to create your own, on other GM vehicles, by using a relay and a line from the windows or sunroof wire in the harness. This would prevent the engine noise or window motor noise I mentioned in an earlier post and provide adequate amperage to power the radio. Please see diagram of a Bosch relay. #85 goes to window power (RAP), # 86 goes to ground. # 30 to 12V (constant/unswitched), # 87 to radio power. All told, 15 minutes and 20 bucks. CC, this is where you come in. Where is the power lead for the windows?

http://www.parts-express.com/resources/relays.html

The driver (and passenger) door modules are supplied with B+, and controlled over the class 2 buss from the switch assemblies. The window motors are integrated into the modules and as such, do not have an accessible "switched" power lead to energize the coil of an aftermarket relay.

CC :cheers

looks like someone has to buy a module!

Question. (just to get folks thinking about a work around.)

Wouldn't a relay powered by a wire that remains 12 volt enabled (RAP circuit) and, that requires just a little amperage to activate it, be a fix? The amperage would likely be small enough to not be a factor for the existing fuse circuits. The controlled contacts could handle lots of amps and be connected directly to, via user installed fuse, the battery.

If the RAP circuit is not energised during normal "run" or "accessory" periods, power to activate the relay could be pulled from another circuit that is hot and then isolated from each other via the diodes.

Archimedes (I hope I'm right) said something like "Give him a lever and a fulcrum and he could move the world".
My thinking is that with relays and some diodes "Yes, you can get this to work".

My point is merely to get the folks that know a lot more about the circuitry of this car than I, to think "out of the (proverbial) box".

Jack

I thought I responded to this but it was late.

I really do not want to have to buy a module. It looked pretty complicated as well.

I like the relay option.
There are two full time hots real close (cigarette lighters) I could tap into one and put in the relay to the radio.
OK CC Tech Man.
Can you help me with a trickle power to keep the relay hot after the ingnition is turned off? but closes when the doors open?
I really thought this was going to be easy.
What a pain in the butt.
I am almost ready to giv.... NO WAY. I am going to figure this out darn it.

Hey Spott,

You would have to find a power circuit that is already utilizing the RAP (windows, sunroof on other cars), etc.