1999 Ford Cobra Manual Fan Switch Installation
These are the procedures I used to install my manual fan switch.
Follow the instructions carefully and you should not have any problems. I can only confirm this to work on 1999 Cobra's and will not be held responsible for any damage that may occur to your vehicle if you opt to try this.
Basically, all you are doing is creating a ground, which completes the circuit and activates the engines electric fan. Normally, the EEC will cycle the engine fan on when engine temperature reaches 210 degrees F.

TOTAL TIME:
1.5 Hours with beer!

MATERIALS USED:
** 1 each - 12 volt DC single pole rocker or toggle switch
** 1 each - "T" Tap-In Squeeze Connector
** 2-4 each - 18 gauge wire connectors (crimp style)
** 1 each - .5 Amp in-line fuse holder and fuse (1/2 Amp)
Electrical tape

** All parts were purchased at a local automotive parts store for about $10.00

TOOLS USED:
Exacto knife
Wire stripers/crimpers
Soldering iron, solder and flux
7mm socket for grounding to harness bracket

NOTE:
See Figure 1 during installation for wiring diagram if written instructions are not clear.
CAUTION:
 DISCONNECT BATTERY AND REMOVE KEY FROM IGNITION BEFORE PROCEEDING

I used a small quality metal toggle switch, and a Dremel tool with a small drum sander bit to make the correct size hole in the dash trim.

CAUTION:
 Using a standard drill bit will grab the plastic and tear it up.

 

The indicator light on top of the dash in the center is my shift light. More info on that in the MafterBurnerPlus page.
You'll need to remove the plastic plug securing the passenger side kick panel. It just pulls right out. Next lift the front of the drivers side door scuff plate and pull the kick panel off and place out of the way.
Now you can see the wiring harness mounting bracket and the EEC mounted up and behind it.
Once you decide where you want to mount your switch, measure out enough wire to reach from the switch to the EEC (add an extra 12" to play it safe).

NOTE:
This wire is hidden by running under the dash and underneath the carpet.

Solder the black wire onto one of the rocker switch posts. This black wire is going to be your ground wire. I grounded mine to the metal bracket supporting the electrical harness plugs at the EEC, using the existing bracket bolt. Solder the red wire onto the other rocker switch post. The red wire connects to the "T" Tap-In squeeze connector you will install on the pin #46 wire. Install the switch in the dash and feed the wires down under the dash, under the carpet, through to the kick panel. Connect the inline fuse holder with fuse to the end of the red wire using the crimp style wire connectors.

NOTE:
The inline fuse holder should have it's own wires attached on each side of the fuse holder.

NOTE:
The fuse is for safety purposes only.

Next locate the LIGHT GREEN wire with the PURPLE STRIPE within the big wire bundle coming from EEC going to the firewall.

NOTE:
You may have to remove some electrical tape to locate the correct wire.

CAUTION:
 MAKE SURE YOU LOCATE AND USE THE CORRECT WIRE
DO NOT use the LIGHT GREEN wire with the PINK STRIPE or the DARK GREEN wire.

When you locate the correct wire, tap into it using the "T" Tap-In squeeze connector, also connecting the end of the red wire into the "T" Tap-In squeeze connector.

NOTE:
Be sure to squeeze the "T" Tap-In connector together securely so you get a good connection on all wires. 

After the "T" Tap-In squeeze connector and two wires are secure, tape the connector and wire bundle back up nicely. Next connect the end of the black wire to your ground point. At this point everything should be connected and ready to test. You may now connect your battery and turn your ignition key to AUX, turn on the fan switch and you should hear the fan turn on at high speed.
Next reinstall your kick panel and scuff plate that is it.

FIGURE 1
That's it. If you are sitting in hot traffic and need some immediate cooling, just reach over and flip the switch for as long as you wish. Works great for me, hope it works great for you.