The rear hatch button on my Focus stopped working years ago. I had a mechanic look at it but he told me it was something in the electric system and he would have to charge me a diagnostics fee to be sure. So I used the keyfob instead. I searched several times for solutions but it was not a big enough problem .... until the keyfob stopped working. Before any other diagnostics, try this......
The release button is a triangle located just left of the steering wheel on the dashboard. >>> PUSH ON THE VERY BOTTOM POINT OF THE TRIANGLE. PUSHING IT ANYWHERE ELSE WON'T OPEN THE HATCH <<<< (!!!!!!!!!!!)