UPDATE: I now have Wiring Diagrams for adding the MF steering...
T18c Pin - color/stripe - function
1 - orange/brown - CAN Low (in 2002+ cars that use 451 relay and CAN)
2 - - no connection
3 - orange/brown - CAN High (in 2002+ cars that use 451 relay and CAN)
4 - black/white - Cruise related, clip on to wire from T10s/4 or T10s/7 from signal stalk, or tap-in to T10e/3 (connector in water-tight box)
5 - lavender - REM wire for remote control of radio, to T20/11 "green" connector behind radio head unit, not needed when using 451 and CAN
6 - green/purple - K-wire (diagnostic wire) T16/7 in instrument panel wiring harness, (OBDII port), below inst. panel, left
7 - - no connection
8 - red/yellow - Cruise - tap-in to T10e/2 in water tight box
9 - brown/yellow - connect to horn relay, S1/6 (bottom left on relay panel, marked "53"), cut wire that is already connected there (it currently goes to T5b/3 on steering wheel) leaving a stub of a few inches from S1/6, and crimp T18c/9 to the stub of S1/6
10- brown - Ground, 1 in instrument panel wiring harness (Brown wires above clutch)
11- - no connection
12- black/red - 12V switched, connect to Fuse 5 in fuse panel (7.5 Amps) When connecting, you should splice this T18c/12 wire AND the wire from T5b/3 that you cut from S1/6 above together into the wire from Fuse 5. Therefore 12V switched from Fuse 5 should go to the middle of T5b/3 on cancelling ring AS WELL AS pin 12 on T18c-- T18c/12 does NOT need this w/ CAN (451), BUT T5b/3 STILL DOES!
13- red/green - 12V power, connect to fuse 40 in the fuse-panel but if you don't do that, you should use an in-line fuse
14- red/grey - Cruise - tap-in to T10e/9 in water tight box
15- grey/blue - ILLUM wire - tap in to T3c/3 in instrument panel light dimmer switch... Not needed w/ CAN (451)
16- blue - Cruise - tap-in to T10e/1 in water tight box
17- - no connection
18- yellow - Horn, T5b/1 on cancelling ring (at steering wheel) you will probably have to add this wire, it is on the far right of the yellow T5B/1 connector on the steering column as you are looking at the steering column.
Some more info:
451 is the newer relay that you use with 2002+ cars with CAN Bus. 452 is the older relay that you use with 1999, 2000, and 2001 cars that use 3LB (12V Switched, Illumination, and the REM wire). T18c is the connector (pictured below) for the 451 or 452 relay in the relay panel. T5b is the connector on the cancelling ring where the steering wheel attaches. T10s is in turn-signal stalk, T10e is in white Water-tight box in the plenum chamber on the driver's side. I got to it by laying the driver's seat all the way back and lying upside down with my head under the dash and my legs on the headrest. It was a pain in the butt (and the lower back), but I'd rather do that than removing my windshield cowling to access the white water-tight box from the top-side. I used gel-filled wire-taps to "tap in" to the wires in T10e, rather than cutting them and re-crimping.
Here is the origial signal stalk on a car WITHOUT MF steering...
Here is the T18c connector wired for the 451 relay with CAN (missing pins 5, 12, and 15). This configuration would be used with the 451 relay for cars that use CAN...
Here is the left half of the wiring diagram for T18c...
And here is the right half...
Hope this helps!
Wes