Mine didn't work either. The first thing is to determine if it's electrical or mechanical.

The Haynes manual gives some quick steps for testing voltage on the OD solenoid wires. (I've got a manual tranny) The gear shifter must be in fourth gear and there is a switch for detecting this.

Anyway, luckily my problem was electrical. Disconnected and frayed wires. From working on it and reading posts here the most likely culprits (besides the wires themselves) are the tranny fourth gear switch thing, the relay (behind the radio above the console. I got to it by taking the glove box out) and the engage button itself.

Lots of posts simply say change the tranny fluid.

Mechanical, I don't know. Solenoid would be easy because it's "right there" on my tranny. Anything after that is beyond my scope of experience working on these.

Hopefully it's something easy like a disconnected wire. Others will probably post with better and additional advice. -k