Security and Central Locking.

The '86 Mk1 has some strange omissions; although it has central locking, this only works from the panel inside the drivers door. So turning the key in the driver's door from the outside of the car, only locks the drivers door. Similarly, locking the car from the passenger's side, only locks that door. 

The addition of a remote control system that locks all the car doors has to be a good idea.

Here in the UK, the Sparkright SR75H System, available from Halfords and other outlets, is in my opinion one of the easiest to fit and meets all the usual requirements.

This costs around £40.00 and has the following features.

1) An siren alarm sounds if the car is physically hit, that is any attempt made to break a window etc.

2) A siren alarm sounds if any  door is opened, or any other action that causes current to be drawn from the car battery takes place. 

This last feature works by monitoring the battery voltage, and any minute change, caused for example by the internal courtesy light coming on, triggers the alarm.

3) Remote control of the alarm and thus all the above features is by a key ring fob. 

In addition to all the above, a central locking accessory is available that will lock all the doors when the alarm is enabled and unlock all the doors when disabled.

Fitting is very easy. The main unit sits in the engine bay (it can be seen mounted on the firewall in the engine bay picture on this site. The box with a red label on top). Connections are only needed to the battery itself. Its a good idea to make the actual connections into the main fuse box and to do it in such a way that the wiring is concealed. It is not too clever if a villain gets into the car, the alarm sounds and all he has to do is open the engine compartment and chop the alarm wires.  Wiring to the fuse box, running the wires behind the trim where possible, and when the wiring is done, spraying all the new wires with matt black paint, all help the common cause of keeping your car yours.

The unit comes with a remote LED that can be fitted in the heater control panel area. My car has a small knockout area here ideal for such purposes. The problem with LED's is that they are not too visible in bright conditions, and I have replaced the LED with a very bright incandescent lamp. This needs a transistor driver. Details of this supplied if you Email me. 

Sparkright make for a reasonable price a central locking accessory. This connects to the two central locking wires in the drivers door  panel. They are the two wires that appear on the plug towards the front of the car. Applying an earth momentarily to these unlocks/locks all the car doors. I made up my own unit to this. This consists of a transistor driven relay and two capacitors that apply a momentary pulse to the door lock leads as described above. The Sparkright unit is not expensive and is probably the way to do the job without invalidating the Sparkright warranty.

In conclusion, this is very worthwhile addition for a reasonable cost.