Replace starter switch
 

How would I go about removing/replacing the ignition switch for a 73? I couldn't figure out how to get to anything behind it, though I just took a brief glance at it. Any suggestions would be appreciated!

Pretty much, the whole ignition has to be removed. I know a man who does it in the car, going where you cant see and getting the job done but working upside down I dont have the tolerance for it.
Take the seat out. remove the trim around the key. Use a dremmel or file or chisel to get the break off bolts out that hold the switch in place. remove the knee trim on the lower dash. unplug the back electrical connector. There is a lock stud going over to the steering wheel shaft, loosen and remove. Thats is why you need the knee trim removed. When youre removing the unit, there is a small electrical connector to remove.
Simply described, Its tedious but doable.
Bruce

Bruce has outlined it pretty well for you, though there are some minor variables through the years.

If you are replacing only the electrical part of the switch, it can be done without removing the entire mechanism but it is a real PITA to access the top screw from behind. Additionally, in my 73.5 at least, the small screws holding the electrical portion are slot-head screws--not phillips head like later cars--making it really hard to get enough turn on that top screw. I have done it using an improvised set up of a long flat-head bit and small open end wrench (all while on my back on the floor of the car) and it worked. It's not that difficult to remove the entire mechanism as Bruce described to access the electrical part, and when you reinstall, you can substitute the breakaway bolts with allen heads, if you wish.

Oh, on a 73, it's not necessary to remove the lower knee pad to loosen the lock nut and bolt holding the lock into the steering column. I would also suggest you do not remove the bolt--slowly loosen it to the point where you can slip the lock away from the column.

are you sure it's just the electrical portion?
I would suggest you remove the whole switch to do properly.
Remove seat and steering wheel.
Remove switch cover.
Remove kneepad.
Use a lefthand drill to remove bolts after centerpunching.
You'll also probably have to remove pop rivets from backing plate.
Loosen locking allen bolt with one of those ball ended allen wrenches.
Remove plugs in back and tag.
wiggle out.
I tidied up all the wiring in back while I was in there.
Full day job.

Wow, really had no idea what I was getting into with this...

On the 55 Jag, the dash folds down, you unscrew the switch and you're done.

How do you remove the switch cover?

I don't think I have a kneepad

Why do you remove the seat?

I did mine - 81 SC without removing the shear bolts and pop rivets. You are on your back and it does take patience to get the top screw (mine are flathead screws as well). If you do try to do it without removing the whole assembly, like RS said, removing the drivers seat a must so you can get on your back and get it done.

So, let me give you the bad news - after I did the job, my new electrical portion went bad in the start position in about 2 months. So, I had this hole in dash next to the key that used to be the Clifford alarm keypad. In that hole, from the local car parts place, I stuck a push start button and wired it by folding the wires over into the pins and sockets of the ignition cannon plug. So, I just turn my key on - push the button - starter turns first time every time. Total cost - $9.99.

Yea, i was considering going the pushbutton route as well.

How do I find which wires I need to do and what do you mean by folding the wires into the pins?

The wire from the switch to the starter is yellow, and if you look under the dash at the back of the electrical portion, you will see a socket plugged into it. The wire loom from that socket run a short distance to the bulkhead where it terminates in a plug that plugs into another socket in the bulkhead. The yellow starter wire is exposed from the loom and has a connector on it. You can separate the yellow wire at the connector and either splice or connect a jumper from the side of the wire that enters the bulkhead to your start button. Now, all you need is another wire to the remaining terminal of the start button that is connected to a switched hot. Once connected, turn on the key, press the start button, and you should be good to go.

If you cannot find the yellow wire and its connector under the dash, there is another connector for the yellow wire inside the trunk, just as the wire looms exits the bulkhead.