So you are wheeling and you hit your flag style mirror on a tree, didn't break the mirror but now it flaps around, whats wrong? Well you likely broke the inner support arm, very common.
Lets have a look at what you did: (Should mention that this is a signal mirror, we all know how valuable these are)
Picture on the left shows the mirror with the support arm, one on the right shows where the arm has broken off.
Lets fix it.
First thing you want to do is visit your local junk yard, ebay or what have you and purchase a regular manual flag mirror for the side you need. No use spending the money on a powered one, and even better if you can get one with the mirror broken as you likely get it for FREE! All your after is one with the support arm still intact.
Here is what I got for 20 bucks, yes I got both sides - I like spare parts and he likely would have charged me the same for one or both.
First remove the little torx screw that hold the rubber seal in place
With the rubber seal removed you now have access to 1 of the 2 torx screw that hold the support arm in place.
The second screw is located at the pivot joint
There you go the arm is off and ready for reinstall, now repeat the process to the mirror with the broken support.
You have one more challenge to tackle, the plug on the wire harness will not fit through the hole in the support bracket. :banghead
You could pop the mirror off and unhook the harness from the board but you could risk damaging the mirror - yes this is how they suggest you do that, with a screw driver in the corned about an inch in. No way in hell was I going to do it to a signal mirror.
So instead i took the connector apart, reach down in and remove the red lock with a pick, than the pins can be un-clipped and you'll end up with this.
Now install the new arm, you don't need me to show you as you now know.
That is it, now slap it back on your Bronco