viper 5704 won't return signal

I have a Viper 5704 installed on my F150 and recently it won't return a signal to the remote. It will arm and disarm but the lock/unlock indicator on the remote doesn't change. The remote just buzzes and the screen doesn't change. What do I need to do to fix it.

Had the same problem with my Python 574, I thought it was the remote ,so after programming the new remote it turned out that the problem was the 574 brain , tried everything to fix problem but nothing worked , so I ended up replacing the brain, problem fixed. ON a small note , I do tons of Avital,Python and Viper two way systems and unfortunately I see a lot of them that are bad right out of the box and I also have lots of returning bad brains. DEI needs to step up their game.Not meant to bash them but it gets a little annoying sometimes.triniforever