I've never had to replace that switch/sensor on this car. The bad is that it appears to be round in the service manual drawings. The small hex nut device (that the sensor threads into) is actually a self sealing Schrader valve (that's good) The factory set the sensor torque to 53 inch pounds (4.5 foot pounds). IF you can get adjustable pliers (what I call water pumps) around that smooth round sensor, it seems like it wouldn't require much force to break the torque setting on it. You then might be able to get some fingers to surround the sensor, to manually thread it out. The Schrader valve will most likely leak out a touch of refridgerant (under pressure) until that Schrader valve self seals itself. The install would unseat the valve an leak some more. So threading in with as much speed as possible is the thing to do. Once the "O " ring sets into its recess, the leaking should cease. Then a little torque with the pliers to complete. If you think some style of pliers can get in there, it probably would be best to line the jaws with a few layers of duct tape when tightening to keep damage control at a minimum. That's the best that I can think of for now.
There's no way you can fit pliers there. You can't even get a small open end wrench there. It's a 14mm nut at the base of the sensor. I just got a crowsfoot socket wrench for it. I think that's the only way to do it. I'll try it in a few days.
That's a lot different than the drawing in the service manual. I know there is a funky tool called a basin wrench (I think). It was designed to allow you to get up behind a bathroom or kitchen sink (with minimum tool rotation room). It has a flip-over self adjusting pipe wrench jaw design connected to an extension with a T handle. It allows you to grab a hex nut or round surface item. As you rotate the T handle, the jaws grip tighter an tighter. If you get some rotation from the item (but run out of twisting room), you would then rotate it the other way (at which time the jaws relax). that action allows you get back to your starting position, an repeat.