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Success: OEM Power Folding Tow Mirrors on a 2012

21K views 23 replies 12 participants last post by  dsptech 
#1 · (Edited)
3/31/19 Folding Mirror Update:

I've had more requests than I expected for the 3d printed parts. I decided to upload the .stl files to thingiverse and make them available for others to print. I'm also willing to print these parts and ship them to you for $150. Please read the writeup below carefully though and understand that you will need access to a mill (manual bridgeport type is fine) and drill some holes in your door panel.The holes are entirely covered by the mirror and not visible whatsoever. The parts will also require some amount of finish work (bondo, sanding and paint).

The .stl files can be found here. Each housing is 4 pieces that need to be glued together. I did this so that it can be printed on most desktop FDM printers and to minimize support material requirements. I've also included the milling fixtures that hold the die cast parts at the correct angle so you can face them down. There is also a drill jig that can be used to locate the new holes off of the existing holes.
https://www.thingiverse.com/thing:3529719

Creating these models did take a significant amount of effort and time. I do request that if you download these files you consider sending me a tip so I can continue to fund these types of projects.
I think $50 is reasonable but will leave that to your discretion.
I am accepting donations here: https://www.paypal.me/sormaz

Also please be aware that I am making this data available only for personal use. Please do not try to resell my work.


Original post:

Well I've finally done it. After having some chinesium "new style" manual fold tow mirrors on my truck for over a year, I got fed up with the bad chrome fading and not having the coolest feature the fancy new trucks have, the power fold.

I now have what has been referred to as "the holy grail". Fully functional OEM power folding tow mirrors, with power +memory tilt (reverse function works also), heat, turn, clearance lights, puddle lamp etc.

Thought this was cool enough to share. There is a possibility I'd over this as a service for folks, but it is quite a bit of work so I'm not sure I'd want to take that on, and cost would be pretty high. Maybe willing to offer a DIY kit of sorts - will gauge interest in the near future.

Here are the steps required to retrofit OEM powerfolding tow mirrors onto a GMT 900 truck:


  1. Create new plastic truck-side housings
  2. Modify mirror mount bracket
  3. Drill new hole pattern in doorpanel
  4. Invert up/down mirror tilt motor direction
  5. Repin connectors
  6. Install and Flash DL3 powerfold window switch modules (these exist for the "small" power folding mirrors that were available for our trucks)

Step 1 is probably the most prohibitive. All aftermarket retrofit options utilize a GMT900 style mounting bracket (the part that physically bolts to the truck) which is a lot smaller than the bracket that houses the fold mirror. This means that there is no readily available plastic cover that fits the motor housing, and also matches the door profile of our trucks. Luckily I was able to acquire cad models for both style housings, got them drunk and made a baby.
I printed the housing on my buddies 3d printer, smoothed with bondo and abrasives, then applied a texture coating and paint to match the look of the injection molded part. (this is the time consuming bit)


I was pretty satisfied with the result. This picture shows the OEM 2015+ housing (right) the OEM 2012 housing off my truck (middle) and their love child (left).


Step 2 is to hack up the beautiful die cast motor housing to make it fit your truck. This is not really a reversible process, and the only way I know to get these is to buy an expensive mirror assembly, so you are committed at this point. First order of business is to use the bandsaw to lop off the front corner of the housing, or if you are like me and just too excited about how well your freshly replaced blade is cutting at 2am, you pay no attention as you cut off the top corner, throw a couple things, go home, come back and JB weld the sucker together.
Again I made use of the 3d printer to make a milling fixture that holds the housing at the correct angle. Machine down a significant amount of the ribs, locate and re-drill and tap the remaining 3 stud mounts for a 12-24 thread.


Step 3 is fairly straightforward, I didn't take any pics (will next time I take the mirror off), but created a template to locate the new holes off the existing holes and drilled them through. One of them is pretty close to an existing hole so it becomes a snowman, but not overly concerned about it as it is the lowest hole and primarily loaded in compression.

Step 4 was a nice surprise, I installed the mirror to find that the up/down tilt actuation was reversed. This wouldn't be too big of a deal, but with the memory function enabled on the mirrors, this causes it to drive all the way to the down position every time i unlock the truck, which is not super useful. So again the mirror gets disassembled, motor removed, cut out the integrated wires for the up/down motor and soldered on new jumper wires to cross them over. Luckily these motors are available individually (p/n 22919754) for about $50 if you screw it up.


Step 5 was actually pretty straightforward. I left my diagram at the shop but will upload it when I remember. Thankfully the new mirrors use the same connector family so the pins are actually the same. Most pins map over to connector J3, but I also had to buy p/n 15127040 which is J7 on the diagram. J7 gets the power fold pins, as well as the tilt position sensor pins. All of this info is available in the electrical manuals available online. The harness ends up a little short to reach the window switch, but with some massaging you can get it there.

Step 6, finally you are going to need to install p/n 20835553 which is the window switch assembly with power fold buttons for option DL3. I couldn't find a reasonably priced bezel with the brushed aluminum finish, so I just spent some time with a dremel adding the additional button cutouts, which actually turned out really well. On the left is my stock window switch, and the right is the DL3 window switch with the power fold buttons. I don't have a before picture of the bezel, but you can imagine I only had to trim back the top of the black part that interfered with the new buttons.



And that's it, job done. Click 2nd pic for video:


I'm about 50% through with the passenger side mirror, will update if there are any surprises on that side. Haven't gotten to step 4 yet, kind of interested to see if it has the same issue. I suspect either both l/r and u/d will be inverted or both will be correct, as it appears to be the same motor mounted at a 90deg angle.

I'm also working on something else pretty cool - will post a separate thread soon. I have a prototype power extending actuator built that should be compatible with both OEM and aftermarket versions of this style mirror and add some pretty sweet functionality if you are like me and forget to pull your mirrors out every time you hook up a trailer and have to pull over at the gas station before the on-ramp to do so. teaser here: https://www.instagram.com/p/BpTld85nxEB/
 
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#2 ·
That is pretty cool. When you get the passenger side finished, it would be nice if you added pics of the switches on the inside located in your modified bezel.
 
#3 ·
This is really cool, and thank you for taking the time to post and give detailed information.

The good news is that boost auto (I know, they are aftermarket) is making a power folding set for the GMT900. I am told it will work with the factory wiring. Stay tuned.
 
#4 ·
Now if they can only make them power extend as well.............That would be SWEET!!
 
#7 ·
Passenger side is done. Feels good, now my truck isn't winking every time I press the fold button.

No real surprises on that side. The tilt control is the same as the drivers side (only up/down needs to be inverted).

I should also note that the passenger window switch does not need to be replaced, but does need to be reprogrammed for the DL3 option to enable to fold output. It receives the fold/unfold command over the low speed lan bus, so no wires need to be run across the truck to do it this way.
 
#8 ·
That is really cool but damn! You musta wanted those power folding mirrors BAD! LOL

Awesome work and yeah, I know that sometimes it's just something you talk yourself into and becomes a challenge and thus "fun" work.
 
#14 ·
Gotcha! Again, awesome work and keep us updated!
 
#15 ·
Did you ever get the power extend working? If so , when can we expect the kit to be available?
 
#16 ·
Apologies for the lack of updates, busy over the holidays getting ready for a cross country move.

That being said, I'm happy to say that I've had the extenders fully functional on my truck for about a month now. I've been able to make some hardware and software adjustments and have a solution that I'm really happy with. Quiet, smooth and fast.

For 07.5-13 trucks with door modules (this style buttons, with or w/o fold buttons), the actuators can be controlled using the mirror adjuster d-pad with the selector in the center position OR automatically deploy when you engage tow/haul mode.

For trucks without modules (ie, these buttons) then you will need to install your own switches.

For new trucks, unfortunately they changed the buttons to be on a LIN network (previously single wire CAN). I am planning to develop a module to interface with these, but for now you can either add manual switches or install them in parallel with the fold motors, so that they will extend whenever you fold out and retract whenever you fold in.

I'm trying to have a few kits ready to sell in February. I'm trying to keep the price as reasonable as possible, however with small qty's it is pretty hard. I'm looking at a rough price of ~$380 for a databus enabled kit and ~$300 for a DIY switches kit. That would include both left and right actuators. I don't think I can get it much cheaper than that and still be worth my time unfortunately. Let me know if that totally kills interest - trying to be as straightforward and open with you guys here as possible.
 
#17 ·
What all is involved in installing and connecting up the set with the first light switch you showed.

That is my style but no folding switch since my truck came from the factory with the Tow Mirrors which never had a folding option.
 
#20 ·
Hey Folks, I added some info to the first post for those that are trying to add power folding themselves. I'm offering the plastic printed housings for sale and also included a download link if you have the ability to print them yourself.

I just moved cross country so the extender kits have been on hold. I'm working on those again now, so expect updates soon.


It's pretty easy. You pop out the old module (the plastic trim is held in by snap fits) and unscrew the module from the bezel. You can buy a power fold module with the bezel but they can be kinda hard to find so I opted to modify my bezel with a dremel to fit the extra switches. Electrical connector interfaces are identical on the 2 modules, but the new module will need to be flashed for your VIN. I did this using the ACdelco TDS service (small fee online) since I have a MongoosePro GM, but you can have the dealer do it as well. Should only be ~$50 but YMMV. Just tell them you are adding RPO code DL3

So how do we get on board ? I want one
See above! More info coming on the power extension kits soon.

What about for the 2006 style trucks? Been looking for powerfold with all the options for a long time!
Sorry but this is not something I am likely to work on. You can blame the guy that stole my 2004 LLY! I probably would do it if I still had that truck.
There are companies that sell aftermarket manual fold mirrors that the power extend kit I am making should work, but I don't think there are any options for power folding unfortunately.
 
#22 ·
Hey Folks, I have 2 adapter kits ready for sale as mentioned above. Additional sets are in process.

Please ready the first post of this thread carefully if this is something you wish to pursue. Take special note of the following:

  • This mod requires complete disassembly and irreversible modification to a set of mirrors to complete.
  • This mod requires access and experience to use a milling machine. I am not responsible for any damage that may occur. Common sense, good practice, and additional tooling may be required.
  • The plastic pieces I am offering are UNFINISHED. They require sanding, bondo, more sanding and paint before they will match the factory plastic. This is a bit of an art, and will require patience and effort.
  • The plastic pieces I am offering are of PROTOTYPE construction. I have reinforced them to the best of my ability by applying epoxy to the back surfaces, however it is not reasonable to expect them to have the same durability as OEM injection molded parts.
  • Vehicle configurations vary, and additional steps may be required to ensure compatibility with your truck.
  • The front caps are not included and must be reused from OEM mirrors

The following album contain images of the first set I have ready for sale. The texture and quality will be representative but by nature of the manufacturing process each piece may have unique imperfections:
https://imgur.com/a/ySeDmGC

If you are interested in a set, please PM me and we can discuss the specifics.
 
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