How to add cruise control illumination to 94/95 SCs
As most of you know or have found out after trying to replace nonexistent bulbs, our interiors lack a lot of illumination that is normally found in modern cars. The MN12 existed right between the era of having to flip on the map light to see what button youíre pressing and the current era of having to adjust the dimmer so the backlighting from the ďtrunk releaseĒ button doesnít blind you. From the bare bones functional sense you can confidentially use the radio, adjust the climate control, operate your windows/locks, and see all of your instruments. Anything else like cruise, headlights, mirrors youíll have to sense and live with the rather incomplete looking lighting scheme. Until now.
WARNING: This is not for the faint of heart, you will have to live with a two things after this conversion:
1) You will not be able to use a single part from your existing steering wheel other than your airbag, even the hardware is different.
2) The illumination is limited to blue. The buttons are molded in translucent blue and painted black from the factory.
If these aren't a concern, read on...
Mark VIII's received cruise control illumination from the 1995 to 1998 model years. They use a special clockspring with 5 (rather than our 3) active terminals (excluding key in input), the added pins are dedicated to illumination. The circuit itself has 1 small incandescent bulb per pod and 1 LED in the right side, the rest of the cruise circuit is virtually identical to the MN12/SN95. The buttons themselves are translucent and allow for light to shine through whereas the MN12 and SN95 buttons are solid black plastic with the lettering printed on them.
You could theoretically swap the complete steering wheel and clockspring from a mark VIII directly into your MN12 and call it a day, however the steering wheels are wrapped differently and don't match the grain of our airbags particularly well. The Mustang wheel on the other hand is finished identically to ours despite having completely different hardware and electronics inside them (See illustration). For this how to I'll be covering the latter since this project revolved around my FR500 steering wheel.
If anyoneís still wondering, the MN12 wheel and buttons unfortunately wonít interchange. The cruise mounting is different as well as minor proportions such as the switch plates, pivots and even the spacing between the spokes. It seems to be sheer luck that the Mustang switch plates and circuit boards interchange with the Mark VIII units. It appears that early on (93/94) they were 100% identical to the SN95 other than the bases. Itís a wonder why Ford didnít equip the higher level Mustangs such as the Cobra with these considering the illumination note is even the same for the 94-00 Mustangs.
-Phillips head screw driver
-Small flat blade screw driver (1/8 - 3/16 or so tip)
-Needle nose pliers
-Socket wrench with T50 Torx socket and 8mm socket
-Soldering iron and solder
-Shrink tubing and electrical tape
-An Electronic Vacuum Troubleshooting Manual would also be valuable to have.
-1994-2004 Mustang Cruise equipped steering wheel and plastic shroud (the part between the column and airbag). If you too have been considering the FR500, now's a good time to grab one.
1994-2004 Mustang horn pads, wiring and hardware. I actually suggest sourcing these from a NON CRUISE equipped Mustang as they position the MN12 airbag much more flush with the wheel. The terminals also match the Mark VIIIís horn connectors better.
-1994-2004 Mustang cruise control buttons. Don't be too concerned about condition as you will only be using the mounting bases.
-1995-1998 Mark VIII cruise control buttons and wiring harness, don't worry if the mounting tabs are broken. (Note: Cruise buttons in these Marks were monochromatic so finding them in black can be difficult.)
-1995-1998 Mark VIII clockspring assembly and the pigtail from the dash harness
Converting the buttons:
Note: I AM NOT RESPONSIBLE FOR ANY DAMAGE THAT CAN RESULT TO YOU OR YOUR CAR.
Note: If youíre using a complete Mark VIII steering wheel, skip steps 1 through 5.
1) Begin disassembling your SN95 and FN10 cruise buttons by gently prying on the buttons at the pivot points. On the right pod be sure to remove the set accell/coast buttons before resume.
2) Carefully unclip the circuit boards from the bases and unplug the harness connector from the circuit. Mark the connectors and boards to help get the orientation right during reassembly. Discard the Marks bases and discard the Mustangs electronics and switch plates.
3) Run the Mark harness through the Mustang base and connect the circuit board. Before clipping it in you will need to clearance the base using the pliers to break off the alignment tabs and wire channel so the new circuits clear. Once everythingís out of the way clip them in
Note: Some Mustang bases have a smaller opening for the harness to go through, if that's the case enlarge it with a 1/4" drill.
4) Place the rubber inserts over the boards and carefully clip on the switches from the outside in.
5) Mount the buttons to the steering wheel and connect the horn terminals to each horn pad if you havenít already. Set the assembled wheel aside for now as we move onto the chassis.
Note: The Mark harness illustrated had to be slightly modified as it only had 1 connector for the horn pads and two for grounds for some reason. If thatís the same case for yours simply cut the ground wire completely off (this wonít effect operation as itís grounded through the cruise circuit) and splice in an additional connector pigtail to plug into the other horn pad.
Converting the car
6) Unhook the battery and let it sit for a few minutes.
7) Remove the round access covers on the steering shroud, unbolt the airbag and unclip the connectors. Remove the steering wheel after loosening the torx bolt retaining it. Also remove the column shroud, knee panel, and floor vent duct underneath the column.
8) Remove and replace the factory clockspring with the Mark VIII one.
9) Cut the stock pigtail off the dash harness and splice the Mark one in itís place, just match the circuits pertaining to cruise and horn for now.
Note: viewed from open dash connector
10) For the remaining two wires youíll need to tap into an illumination circuit in the dash, the illumination wires are usually LB/R. You can simply run the ground to the chassis or splice into another known ground, an EVTM is very handy to have for this step. (I tapped into an unused terminal in the secondary junction box for my illumination feed, again I strongly suggest an EVTM for this)
11) Shrink wrap and Tape up all of the exposed wires, connect the new pigtail to the clockspring as well as the 2 pin airbag connector and reassemble all of the parts removed in step 7.
12) Install the steering wheel, connect the white cruise connector to the clockspring, connect the airbag to the clockspring, reinstall the airbag
13) Connect the battery, turn on the headlight switch and drool over your new feature.
If anyone has questions/concerns or anything to add to this, feel free to PM me.
Good stuff, thank you for taking the time to document this. Lights are always impressive
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