mine is grounded and still doesn't work, i have the unit grounded to the screw in the front of the radio instead of the screw in the back like some people have been using and the tt turns on but after i set the time and turn off the car it does not countdown but just turns off

 

The screw in front of the radio won't actually ground it. You have to find a screw that touches the metal of the body.

 

i fixed it, it had nothing to do with where i grounded it, it's the red splicing clip that was supplied for the ebrake, it doesn't do such a great job piercing the sheathing on the wires, i just strippped them enough that the contacts on the clip would touch bare wire, works perfect now