Adding pwr fold signal mirrors 08 gmc
 

I got the driver door module, both mirrors so far. What else do I need it looks like I also need to change the door harness'. Does anyone know the part number for the passenger door module w dl3 mirrors. I've got tis and tech 2 to program everything. I just haven't got real deep into it yet and was hoping someone would come through who has done this already.

Had to order both door harness' and the passenger door module. I'll keep this up for those who want to do this in the future. This is for a customer that doesn't mind spending the money. This isn't a cheap mod unless you pirate a donor truck. If all you want is the signal part it's plug and and go. Power fold takes it up several notches in difficulty and expense. This is an 2008 gmc short crew 1/2 ton.

So the heat, and signal is just plug into original harness and thats it? the tow mirrors correct?

I had looked at this a while ago for my 07 reg cab but it got too involved and pricey for the benefits so I settled on the integral signals, auto dimming and heated...that was all fairly easy to do (there is a post on this in here somewhere).

Been a while, but if you are adding the power folding mirrors you need the door switches that are databus modules. Problem here is they are shaped differently so you may need new door panels as well...take a look how they curve down at the back (not sure on 08's and not sure what trim level truck is)....then you need diff door handles and cables as well.

This led to the obvious problem with (my) reg cab is what do you do with the extra two switches for windows that my truck didn't have since all the trucks with power folding mirrors have four switches???LOL

I went so far as to buy upper level door panels, and was looking for switches when I stopped. The BCM was the same on ALL the 07 trucks by part number so that shouldn't be an issue...run the harnesses and you are way ahead of the game with a tech II available...that was my other concern...local dealer wasn't interested in helping and apparently you need a ext or crew vin to add option to the system but tuck is reg cab...LOL

Mind if I ask what the p/n's and prices of the door harnesses were??

Anyway, sorry to hijack your thread. Very interested in how it works out for you, please keep us posted.

I'll get pn's and prices when stuff gets here didn't even look at the stuff just ordered it so I can get it done and get a customer taken care of.

Excellent. Thanks....

I did this on my 07 Avalanche a while back. I copied my post from a thread on the Av board. You can view the entire thread Here.
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I have a 2007 2LT Avalanche. I wanted the DL3 folding mirrors. This is what I went through to get them.

First I bought a set of mirrors from someone who upgraded his DL3 mirrors to the trailer mirrors. Fortunately he had the same wood grain trim as my truck so I was able to get the drivers door switch and trim panel from him as well. We plugged the drivers mirror and switch in before we parted and it worked. I thought that was all I needed to test.

I rushed home and installed the mirrors and much to my surprise the passenger mirror would not fold. The only added feature on the passenger side that worked was the turn signal. I called my dealer and asked if they could fix this by flashing the BCM. They told me there was no way it could be done. They have tried it and it was impossible. All the programing is based on the VIN and my VIN does not have that option.

I then called my salesman and convinced him to let me swap the passenger switch with a DL3 optioned truck for testing. We pulled the switch from a truck on the lot and put it in my truck. The passenger mirror functioned correctly with this switch. Even though the part was identical right down to the part number. With my switch the passenger mirror would not fold and with the borrowed switch from a DL3 optioned truck it would. I further tested this by putting my switch in the DL3 optioned truck and the passenger mirror did not fold.

After talking to the parts dept we figured out the memory module was in the switch and it would have to be programed for the DL3 option. I called service back and asked them to put my switch in a DL3 optioned truck, flash it and give it back to me. They agreed to do this for me on the phone but when I showed up to get it done, they refused to do it. That was and will be my last trip to that dealership for anything.

I then called the preferred dealer of the person I bought my DL3 mirrors from. They were extremely accommodating even though it was a Pontiac/GMC dealer and my truck is a Chevrolet. He said it was no problem to fix this. He also stated they did not need to put my switch in a DL3 optioned truck. They could fix this with a Tech II.

Before they flashed it, I noticed that by installing the switch form the DL3 optioned truck it added the park tilt feature in the DIC. I don't use it but i thought it was cool that I had it now when I didn't before. After they flashed it this feature was gone. After talking to the tech he said the park tilt was only available with the seat upgrade. He then flashed the truck again changing the seat option and the park tilt feature returned.

Three suggestions for those with dealers who say it can't be done:
1) See if they will put your switches in one of their DL3 trucks to program them
2) Swap switches with a friends truck with the DL3 option and have the dealer flash that truck.
3) Go somewhere else

Part numbers I used:
The drivers side switch - 15906881
The wood grain bezel - 15920638

This may or may not work for your truck. Not all 900 platform trucks are wired for this option. From what I can tell if you switch looks like the picture 1 you can do the upgrade and have fully functioning folding mirrors. If you switch looks like picture 2 then you do not have the switch with the memory module and you truck will not be wired for the folding option. Look closely at the buttons for the mirrors. This is where the most significant difference is.

Picture 1
http://ifixsolutions.com/avalanche/switch.jpg

Picture 2
http://ifixsolutions.com/avalanche/switch2.jpg


Long story short, Some (but not all) can add the DL3 mirrors to a GMT900 truck and have all the features work.

Upper switch is databus, lower switch is hardwired (ie not databus-same as all reg cabs) style...also looks to be different door panel as shows cutout for the grab handle. If you install the databus wiring harness in doors and to BCM should be able to run the databus switch but BCM will have to be programmed as well. It all gets rather complicated, probably more trouble than its worth but the info you provided is excellent.

What I can't figure out in this day and age of cost cutting is why would GM develop two different harnesses to do the same thing on the same vehicle line, they could have just used the databus harness in everything and programmed as required to keep the option levels where they wanted them?:confused:

Back when I did this mod the dealers did not have much info on the databus vs non databus trucks. The dealers seem a little more informed now.

I agree It makes no sense why GM engineered two different systems for these trucks. Not only is the harness different but there are numerous electronic and trim parts that are different between the two. There seems to be no rhyme or reason to witch trucks got what system. The mirrors and switch I bought came off a GMC CC truck that had the databus. I have a co-worker with a GMC CC same year and it has the hardwired system. The two trucks are even the same color.

This is for an 08 gmc sle-1 interior. Upgraded to sle-2 with DL3 option.

Must change door harness' bezels, and swap to a driver door module and passenger door module as opposed to the hardwired switches from the factory.Must locate a VIN for a truck that is the same year model as yours and has the DL3 power fold mirrors. This is necessary to reprogram the new door modules and the BCM so everything will function correctly.
25879083 left mirror
25971917 BCM uplevel option
25838267 right mirror
25788838 door harness
25869957 door harness
15906882 driver door module
15906881 passenger door module

Chunked the boxes for the switch bezels last week.
You can get the DL3 mirror option in a option package with the SLE-2 interior and the non-luxury door panels.

Changed all of those parts. Then I reflashed the BCM, DDM, and PDM to the VIN of a truck that had DL3 option. You then have to reflash the radio also because it is VIN locked to the truck and will lock up with the bcm reflash. If you have XM radio the XM will lock out. There is no way to relearn it you must replace the XM receiver with a new never programed receiver. The new xm module will then learn the vin of the truck with the DL3 option once it is installed and the new receiver setup procedure is done using the tech 2 under the special functions menu. Once the bcm is flashed you have to go to special functions in the bcm and select SDM relearn so the airbag will function. EDIT IF your truck has rear park assist this module must also be replaced with a brand new never programmed module because it is VIN locked to the BCM just like the XM module for god know what friggin reason.

This gets everything functioning and working front doors lock correctly windows function and mirrors fold operate and turn signals working.

The rear windows is where it gets fun. There are two connectors one in the drivers kick and one in the removable panel at the side of the dash. These connectors were originally routed into the drivers door switch and were plugged into the drivers door harness and contain the window control wires for the rear windows. Everything in the front doors changes to databus with the DL3 modification requiring these wires to now be routed to the BCM into the gray plug marked X7. The rear windows are now under BCM control. I took the original driver door harness and gutted it so I had all of the wires that ran to the x800 and x700 connector and removed all of the wires except for the rear window control wires that is all that is needed now. This let me plug into the factory connectors without having to cut anything. You have to crimp terminals onto the wires in order to slip them into the bcm the part number for the terminals is SNAC3-AO21T. They are located in DELPHI tray number 20. These terminals are part of the essential service tool kit and are available at all gm dealers. I have the special crimpers to crimp them onto the wire it is a three step crimp procedure. The crimp tool number is J-12085271. Plug these new terminals and the wires into the bcm into the positions below in order for the rear windows to work.

Passenger rear door BCM plug gray X7
Purple down control pin 26 at bcm
Lt-grn up control 18 at bcm
lt blue/white window request 27 at bcm

Driver rear door
Purple down control pin 19 at bcm
DK green up control 28 at bcm
DK blue window request 21 at bcm

With the DL3 mirror option added the control wires from both rear switches are now re-routed to the BCM and are under direct control of the BCM.

When you push the LR or RR window up or down button on the drivers door that command is sent to the BCM via serial data, the BCM then sends the command to the appropriate rear window switch which then in turn rolls down the rear window.

This was a hell of a lot of work the customer wanted it and didnt mind paying for it. He is disabled and could not get out of the vehicle to fold the mirrors in and out to get into his narrow garage. I'm not even going to put prices on parts because gm is changing them daily almost these days. I did this it works beautifully dont let anyone tell you it cant be done they just have to be really familiar with TIS and know how to work around it. This is where and when you enter the VIN for the donor vehicle it will then load all of the correct calibrations for every module present in that vehicle you then program the BCM, DDM, and PDM and radio one module at a time. Then clear all codes when done and everything will work correctly. You dont mess with the VIN information in any other modules since it is irrelevant. The PCM, TCM doesnt care what VIN is in the other modules in the vehicle. The BCM and Radio are the only two that have to match in order for the OEM radio to work. Write down the donor number and keep in the glove box it must be used for the rest of the life of the vehicle to keep everything working. If at any point the BCM, RADIO, DDM or PDM are flashed back to the stock vin the added DL3 options will quit working rt window will quit and the door locks will not work.

GOOD LUCK you must have a through understanding of GM wiring schematics and how the components interface for this to work.

Wow that is some crazy s**t with the xm and all, not surprised though. Great write up!! :nod: