Clifford Matrix RS3-responder not working

I installed a Matrix RS3 on my 98 Dodge Ram about a year ago and it has worked perfectly until recently.  About a month ago the 'Responder' part stopped working; that is, the remote stopped recieving pages and the confirmation alerts when I arm/disarm/start etc...  I thought the problem was in the original remote transmitter (the antenna cap of course fell off long ago) so I purchased the replacement remote (the carbon fiber one from the RS3.5) and programmed it in.  It controls the alarm just fine (arm/disarm/start/etc...)  but doesn't recieve any transmissions from the vehicle (brain), same as the old remote.

I checked the wiring for the antenna in the truck and all seems well.  I'm guessing that since this problem suddenly started without any changes to the wiring that there is probably something wrong with the 'brain'. 

I would welcome any suggestions before I give up on the responder part of my $500 alarm.

Thanks,

Tim

Thanks for the reply.

The plug from the antenna to the alarm unit seems fine.  The actual antenna should be okay, I don't think they can go bad, can they?

I have the 'page mode' turned on from the remote, but I think even when it is turned off I should still receive a recognition page when I send an arm/disarm page.

Any other thoughts?

Thank you