First Gen side mirrors come apart?

There is no "back cover", the black housing is all one piece.

The mirror is supposed to pop off from the mount it pivots on, but generally trying to remove it results in the mirror or the mount breaking, due to age.

I'd suggest leaving the original mirrors alone and get some other used ones to break apart and mess with for possible lighting mods.

I thought about that just getting another one to mess with. But there is a separate piece on the back at least on my 91 there is. See the seam it goes all the way around. I have shoved a screw driver and pried it partially apart. But I can't get it to separate I don't want to break it.

The seam is from there initially being two pieces assembled together, but as you've discovered, they don't seperate easily, and my advice is based on that - they will likely be broken beyond repair if pried apart.

What exactly are you looking to do to the side mirrors that you want to disassemble them? Install puddle lights or side mirror turn signal arrows?

Getting one to take apart might get you some insight into how to take one apart to do as little damage as possible, but in my experience, original first gen mirrors are now 20+ years old, and the plastic is fragile and brittle and they don't come apart without damage that make the disassembly pointless, unless you just want to see what they look like inside. The mirrors are supposed to pop off as well, to make replacement easy, but it seems the plastic mounts / pivot breaks instead of just the mirror popping off the mount, which, again, damages the assembly beyond basic repair.

Yep I want to do a signal mirror mod. I see they sell replacement glass mirrors by itself. I might go that route just break out the old mirror and install the new replacement with the LED attached. That would be a cheaper route cause the cheapest I can get a used mirror to mess with is $25.00 cause there motorized. A replacement mirror glass is only $10.00.

Just got an idea. Maybe I'll go to my pick-n-pull pry apart one in the yard. I don't have to buy it just find out how they come apart..

The replacement mirrors are usually just flat mirrors with adhesive, that you stick over the damaged part of the original mirror surface. They aren't always an OE replacement with the attachment for the pivot of that particular mirror.

You can go to the salvage yard and practice prying out the mirror part to see if they pop out, and see if you can figure out how to do it so it comes out without breaking the pivot, but they aren't going to be very happy about someone going around busting mirrors they could otherwise keep intact and sell if you go around doing it on otherwise good mirrors.