I have had a Phantom 4 Pro Plus for a while and then left the controller in the rain which ruined it.  I purchased a new controller and immediately charged it up.  When I turned it on, the red light was flashing and the unit is beeping.  any idea what to do next?

Did you link it with AC?
It might need a stick calibration

KedDK Posted at 2017-10-21 23:55
Did you link it with AC?
It might need a stick calibration

I do have it linked.  When I press Go Fly, it says "Unfortunately DJI Go 4 has Stopped"

It is linked and when I press Go Fly, it says "Unfortunately DJI Go 4 has stopped"

Please reset the RC first: Settings--system settings--Backup&Reset–Factory data Reset. As for the beeping issue, please try to toggle the sticks to see whether it is the misinformation of sticks isn't centered.

DJI Susan:  I did what you said above and the red blinking and beeping stopped.  When I have both the AC and RC  the status light now blinks very rapidly red/then green, when I press fly I still get the message, "Unfortunately DJI Go 4 has stopped"..

In the user manual it says when the status light on the RC blinks red/green that the "HD downlink is disrupted" which I don't know how to correct the problem

Actually updating both the RC and AC software has eliminate my problem.