1993 Ford Escort LX , starting problem

Good afternoon,

I am wondering if anyone can be of assistance.  We recently purchase a 1993 Ford Escort and are encountering problems trying to start the car and/or lock it.  The Central Locking system is making a ticking sound and it appears the alarm is always activated (not making noise but giving the blinking red light to say it is armed).  We try and start the car and the light goes to a solid red and this is when we hear the ticking sound from the Central Locking System which usually stops after about 20 - 30 seconds.

If we unplug one of the two wires going into the central locking system it appears to bypass the alarm system and we are able to start the car.  Is this the immobiliser, central locking system or a problem with locking system inside the door?  Depending on which way we proceed, we are able to unlock and lock the doors from the outside but this is not consistent.  The same problem occurs from inside the car however it does not seem like a mechanical problem but seem that the alarm is stoping us from starting and locking doors.

Any information and / or diagrams would be greatly appreciated.

Thank you.

Further to the previous message, if I unplug the central locking box, I can unlock/lock and start the engine no problem.  Is this the immobiliser or the Central Locking system?

Any suggestions?