If your touchpad touchpad keyboard cable is damaged,don't need to change new device, just buy this item and replace your damage flex cable , let your trackpad work again.

Identifying Numbers:
-APN: 661-8311
-Printed Part #: 821-1904-A, 821-1904-02
-EMC Number: 2674 or 2745 or 2876 or 2881

Package including:1x Trackpad flex cable

Compatibility:
Compatibility:
-Compatible with MacBook Pro 15-inch Retina Display Late 2013 A1398 (EMC 2674)
For MacBookPro11,2 Late 2013 (IG): ME293LL/A (2.0 Core i7) or (2.3 Core i7) or (2.6 Core i7)
-Compatible with MacBook Pro 15-inch Retina Display Late 2013 A1398 (EMC 2745)
For MacBookPro11,3 Late 2013 (DG): ME294LL/A (2.3 Core i7) or (2.6 Core i7)
-Compatible with MacBook Pro 15-inch Retina Display Mid 2014 A1398 (EMC 2876)
For MacBookPro11,2 Mid 2014 (IG): MGXA2LL/A (2.2 Core i7) or (2.5 Core i7) or (2.8 Core i7)
-Compatible with MacBook Pro 15-inch Retina Display Mid 2014 A1398 (EMC 2881)
For MacBookPro11,3 Mid 2014 (DG): MGXC2LL/A (2.5 Core i7) or (2.8 Core i7)
-Please double check your MacBook's model number "A1xxx" and "EMCxxxx" on the bottom of the laptop to determine the compatibility.

Note:Only compatible with Macbook Pro 15" retina late 2013 - mid 2014 with model A1398.(There are different versions of cable for different years and models ,make sure you are buying a compatible model.)