My MK1 was supplied with one key and it was not able to be remotely opened..
I did have central locking just not remote, if you don't have central locking then you will need to figure out how to fit the solenoids to the doors as well.
Tools needed :
Blue scotchlock's (2)
Optional - Multi Meter
I purchased this unit from ebay, it is a universal one that will do positive or negative feeds to the switch unit.
It comes with 2 remote units (3 button) with keyrings, wiring diagram and a double sided pad to stick it somewhere.
I decided to fit mine behind the radio as I had power there and access to the indicators.
Remove the radio (plenty of guides for that on here)
For my Focus I set it to -ve switched feed by connecting the Yellow & Yellow/Black wires to the gnd wire (Black)
I fed power to the unit from the cigar lighter supply by baring the wires and soldering the feed to them. (Red & Black wires) (Insulate with tape after soldering the wires together,)
The two Brown wires are to the indicators so I used a pair of scotchlock connectors to the wires from the central hazard button. (Blue/Black & Blue/Yellow doesn't matter which is which)
I then fed the 3 control wires (Pink, White & White/Black) to the central locking unit behind the drivers A pillar. Routing them behind the trim and taping to existing wires to keep them in place.
Remove the kick plate and locate the CLU, it is up the A pillar a bit, remove the GREEN connector (connector 1, on mine the BLUE connector was not connected to anything,)
The connector has pin numbers on the back.
All wires are connected to connector 1 the GREEN ONE.
The Pink goes to pin 3 (Black/Yellow wire) (Boot release)
The White goes to pin 16 (Black/Orange) (Lock signal)
The White/Black goes to pin 13 (Black/Green) (Unlock signal)
On mine I had to bare and solder all these wires are they were too small to use scotchlocks on.
Test before refitting the radio
Refit radio and trim, enjoy your remote locking Focus.
Things to note:
The remote's have a LONG range ~50M
They don't lock after a set period after unlocking (my Mondeo used to re-lock if no doors were opened after 30sec ish)
The boot will ONLY unlock IF the rest of the car is unlocked (don't know why)
Indicator flash signals:
Once - Locked
Twice - Unlocked
Thrice- Location finder press the lock button when the car is locked
Thrice FAST - boot open (see above)
Time required about an hour (took me longer to find the CLU and diagnose the no-lock issue.)
Pictures to follow when I take them
Thanks to Dan62 for assisting me in this with wiring help.
Testing I found I could UNLOCK the car but not lock it, this was
traced to a fault in the lock pin wire (16/1) for some reason mine was
constantly at ground, so I just cut the feed from the door switch (this
removes the central locking from the driver door key). When it gets
warmer I will remove the door trim to find the fault.
Hope this is of use to someone else.