Another option is to cut the zip ties on the back mech cable and follow it down the the base of the chair. It can be unplugged from the connector and the mech can be removed with the back cable connected in this way. Make sure you disconnect using the white connectors show in the bottom of the image.

Note: If you do choose to replace the back connecting cable, please make note of the zip tie locations and when re-installing use the exact same cable routing. This will prevent the new mech from damaging the new back connecting cable.