That sounds like the link.
The alarm wiring is normally cut into the central locking wiring under the drivers footwell carpet.
Pull up the carpet and the plastic trim covering the wires.
Hopefully you will find where the wires are joined easily and one of them will have broken off and just want re soldering.
If you find where it is bridged and there is no apparent fault, cut out the alarm wires and rejoin the original ones. That should fix it (the alarm will still work, it just won't lock and unlock the doors from the remote).