adding a trunk release to factory remote

I have a customer that wants to add a hatch pop to his 2011 Kia Soul. there is no button on the remote o I was thinking of just adding a few relays (or whatever is needed) to the unlock wire of the car so all you have to do is hold unlock for a few sec and it would pop a Trunk Release Solenoid (5222T). anyone have any ideas on what it would take???

Chris Carr

GP Customs

Lincoln Ne

does the trunk have an electric popper button inside the car?

could it be as simple as programming a factory remote that does have a trunk button?

if not

if the interior light gets turned on when you lock/unlock the doors, have a relay that when turned on by the interior light, re routes the door/unlock lock signal through a relay that instead pops the trunk.

so to pop the trunk, you would press the lock/unlock button  to lock/unlock and then one more time within the allotted time that the interior light stays on.