the blinking light is called a link light. you should have one on the touch panel, and led 39 on the control box also should be blinking.
go to the hwh website and download a service manual for the 625S system. there is a wiring diagram for the control box, touch pad, and the rest of the wiring harnesses.
if you are not getting a ground signal on the 9000 wire, it may not be the control box. do the diagnosis first. dont replace any parts without being sure you need them.
if you need more help, please free to call me at 602-549-3638. i do work for hwh. i can help. i live in arizona so we are on pacific time right now. my phone is always on. if i dont answer leave me a message. i will call you back asap.
if you dont call me, follow dougrainer's advise, he is one of the best on hwh problems.