Unidentified red wire?
 

There's a small red wire running from the drivers side of the firewall alongside the brown ground wire that attaches near the fuse box. It has a ring terminal but I can't determine what it is for? It looks like it might attach to the battery but I'm afraid to do anything with it until I know what it does.

Here's some pics - 1988 GXL
https://cimg1.ibsrv.net/gimg/www.rx7...a5f618f503.jpghttps://cimg4.ibsrv.net/gimg/www.rx7...20c00f5f2c.jpg

When I bought the car it had an old 80s car phone installed that didn't work anymore. I'm thinking this might be linked to it?

Unidentified red wire?
 

Probably, it isn't a factory end

Unidentified red wire?
 

The picture tells us nothing besides the fact that a previous owner installed some aftermarket accessory. Until you trace it into the cabin, it's anyone's guess what it did/does.

That hooks up to the button on the dash that you don't know wtf it's for..lol

My guess is a 12volt battery feed for an aftermarket deck.

Thanks for input, guys. As it seems to be an aftermarket wire, it's definitely for the car phone (doesn't work anyways).