After not having much luck finding a thread on fixing one- I decided it was time to dive in and figure it out. I wasn't planning on doing a tutorial, but did take a few pictures along the way. Hopefully I can save someone else the $1,000+ that the dealer wants for a new mirror. There is a lot to these mirrors, but that is just stupid.
Before starting- The problem I was having was the passenger side not folding in or out. I could hear the little motor whining, but no movement. All other functions worked fine.
For those mechanically inclined I will cut to the chase- Below is the ultimate problem that needs addressed-
As you can see it is a worm gear setup. The gear is a plastic gear on a knurled shaft. Well the plastic wore, and started spinning on the shaft. Still a snug fit, but not quite enough. Cleaned it up, added a bit of JB weld, and reassembled. Good as new!
1. Leave the mirror attached to the vehicle until all plastic has been removed. Start by removing both mirror glasses. Pretty easy to do without breaking the glass. Position mirrors in the extreme up and out position. Use a 3/16 flat screwdriver and insert from bottom left corner, up diagnolly and twist. You can see the slot in the pictures below-
2. Once those are off, You can remove the 4 7mm screws that hold the plastic housing together. I was not going to make a tutorial, so no picture of this step. If you have color matched caps, there are 2 tabs at the top that can be released and the cap will slide straight back.
3. Next is to remove the plastic covers on the Arms. This might be the hardest part. Requires moving the mirror back and forth to access the release clips. The plastic mounting base cover can not be removed until the arm covers are. Do not worry about the end caps at the pivot point. They can stay. At this point you should have something akin to naked robot.
4. Now remove the mirror from the truck. Make sure the Mirror is in it's normal out position- Not folded in or forward. Extended or retracted does not matter. To do this requires removing the door panel to access the wiring harness. which is easy. Two screws on the very bottom, and two under a access port under the armrest. The speaker cover pops off, and the window switch panel pops straight up.
5. With mirror removed, release plastic base cover. Now slide the extendable mirror half from the base part. It will come right apart. Your mirror should look something like this now:
6. Now reconnect mirror and trigger power fold function to determine which arm moves, if either. For me top arm did not move, bottom did. Each arm is held in place with a cover plate. The bolts almost feel like they are rounding off, when coming out, but are not.
7. Isolate the faulty arm.
8. At this point you can see the motor inside the metal bracket. Having a vice handy will make life a lot easier. To extract remove the screws, and drive the round pin out. Don't worry, nothing will go sproing.
9. Now you need to pry apart the ends of the arms enough to clear the remaining pin, and work the gear box out.
10. Remove the 3 springs from the motor casing. Use a small screwdriver to remove the springs from the side by the plug one at a time.
11. Once the springs are removed, it is smooth sailing. The housing comes apart easily, and is surprisingly simple.
12. Most likely the little plastic gear will slide off the steel shaft- Clean, JB weld, and reassemble in reverse order. Be quick with re-installing the gear and be sure it is seated. Once the JB sets up even a little, the gear won't move without breaking. Be sure the little steel wear discs are at each end and test fit the shaft.
13. Reassembly is pretty much just the opposite. When putting the springs back on the gear housing, use a small round bit as a spacer to make it easier for driving the round guide pin back in through the steel arm- kind of like this
And that is about all I have to offer. Sorry I don't have more pictures, but this really is more intimidating looking then it actually is. Good Luck, and ask any questions for clarification.