94 Overdrive button doesn't work

Got brother's car a few months ago and the whole time his overdrive button doesnt work. Only way for me to get it turned off is to go from park to drive over and over till I land on drive with it turned off.

Apparently he hit it with something he was trying to fit in the back by accident and ever since it's been weird but now its getting bad.

Any appx on how much it'd cost to fix?

I have a 94 Tbird too and I screwed up my overdrive while replacing the shifter button. Apparently, I pulled a wire out of the plastic piece that is underneath the shifter. I ordered the part from a Ford dealer and I think it was like $23. But don't quote me on it, cause it's been over 2 years since it happened. Should be an easy fix. The overdrive button itself should pull straight out. Then pull the staple thing out of the shifter which is located in the front. Now you should be able to pull the shifter straight up. Oh, be careful not to loose your shifter button or spring cause they may pop out.