Rear hatch won't open.

[coyothunter]

New to the forum. I've searched and read anything on here that I could find related to the problem. I have a 2014 500 that is out of warranty. Fiat offered to replace my wiring harness... for about $3000.
Here's my problem:
Wife's car. Last year, the rear hatch would randomly not open. If you rubbed the hatch just right it would sometimes open. Tore it apart and cleaned all connections. most were green and slimy. Worked for a while and now it has quit completely. Tore it apart yesterday and checked for 12v. Nothing. found 2 wires at the boot going into the hatch that pulled apart when i stretched them. fixed them and still nothing. Checked all fuses. All good. License plate light and rear wiper work. Applied 12v to the middle wire on the handle switch and the latch motor worked as it should.
Here:s my question:
How does the lock circuit work on the rear hatch? Relay? Computer? I'm thinking that there is something faulty with the lock circuit that won't allow power to the switch or to the latch. Anyone have a wiring diagram? Any ideas? I do not believe this is a wiring issue, but I may have to find the harness under the dash and test continuity. I guess if I could find the harness under the dash I could check for voltage.
Help Please. This P.O.S. is killing me.
Thanks, Rod

[coyothunter]

Couldn't wait any longer. Sorry. Drilled a hole in the hatch, put a push button in and wired it to the battery. Steal the pos, please. This is the worst vehicle I've ever owned.

[streetsurfer]

Haste makes waste.

[Ando]

Has intermittent problem for 12 months, can't wait 6 hours for help on the forums.

Fun fact: Repeatedly insulting the vehicle of choice of a group of like minded individuals is not a great way to make friends.

Right now I'm gazing at the wiring diagram folder on my computer and chuckling to myself.

I wish you the best of luck in your future vehicle endeavours.