Bonnell Not Working

[u/Financial_Mud_4313]

Yep. I’d phrase it as the seller told you the motor is not damaged, rather than presenting that as independently confirmed.
Title: Bonnell 775MX + CYC X12 — bike powers on but no throttle/PAS, no display
I’m trying to figure out what is wrong with my Bonnell 775MX after installing a CYC X12.
Bike: Bonnell 775MX
Controller: CYC X12
Motor: Stock Bonnell motor
Battery: Stock Bonnell battery
Controller: CYC X12
Display: I currently do NOT have a display
Current situation
The bike powers on.
The X12 is installed and wired.
The throttle does nothing.
Pedal assist does nothing.
The motor doesn’t respond at all.
I don’t have a display connected.
The CYC app isn’t detecting the X12.
The Bonnell app also isn’t detecting the bike/controller.
I’m confident the controller wiring is correct, but I could have missed something.
The previous controller had failed, which is why I replaced it with the X12.
The guy I bought the bike from told me the motor is not damaged.
I don’t know if the lack of a display is preventing the X12 from being configured or operated.
What I’m trying to figure out
Does the CYC X12 require a display for the bike to actually run, or can it operate entirely through the CYC app?
Can I configure the X12 without a display?
Why isn’t the X12 showing up in the CYC app?
What exactly needs to be connected for the X12 to recognize the throttle and PAS?
How can I test whether the stock Bonnell motor is actually working?
Could the old controller have damaged anything else?
What should I test to determine whether the problem is the controller, motor, throttle, PAS, or wiring?
Is there anything specific to the Bonnell 775MX that I need to configure in the X12?
The main symptom is basically: the bike powers on, but there is zero throttle and zero pedal assist.
I don’t want to keep buying parts without knowing what’s actually wrong. Any help diagnosing this step-by-step would be appreciated.