Electrical igntion switch on 1999 Acura TL is common to overheat and been subjected to recall. However, if your car's electrical ignition switch has been replaced previously and the electrical ignition switch burned out again. Then, they won't replace another one for you (which is the case on my TL).
Start by disconnecting your battery. Like any other electrical job, you should always disconnect your battery. Otherwise, it will cost you much more if you accidently fry other electrical components (you will need a radio code or navi code if you have one when you reconnect your battery).
Start by removing the fuse panel
Remove screw from the dash panel. There's only 1 screw here.
Pull corner of dash panel loose
Unplug dash light dimmer switch
Pull on the bottom of the dash panel on the other side until you get it loose
Pull from here to get the last clip loose
Remove screws from the bottom of the steering column cover and then remove the top of it
Flip down tilt steering lock so you can slide the bottom part of the cover off
Unplug the brown plug (this is located under the left side of your dash)
Remove two screws on the electrical ignition switch housing facing toward you (one of them is circled red)
This is where you need to find the "mystery screw". If you lay down and look under steering wheel toward the center console and follow the housing cover (from the two screws removed in previous step) you can see it. Remember there's two screws visible there, you want to loosen the bottom part which is connected to the plastic housing cover. Use a smaller screwdriver or an elastic/pivoting head screwdriver to do this.
Now you just slide out the ignition switch and install the new one. Put everything together back in reverse order. Here is the pic of everything taken out from my car. The highlighted red box is the switch you need to replace.
