Originally Posted by LALEX1

It was the original sensor that came with my 08 vantage. only one of them went out the other 3 are still the original ones. I had a shop remove the sensor and then opened it up myself. Its pretty self explanatory. I will try and upload pictures if I can find them.
1. Remove the clear silicone on one side of the sensor, that will allow you to remove the board with the batteries on it.
2. Unsolder the 2 batteries
3. Resolder new batteries (test solder points with a multimeter to make sure the batteries are giving out the correct voltage)
4. reinstall and add clear silicone again. (make sure everything is sealed so the sensor will work properly.
5. Have a shop reinstall the sensors

Thats it.

I also ended up purchasing quite a few extra batteries with the correct arms (has little metal tabs sticking out of the sides to reach the circuit board).
I'll try and upload pics when I find them
I suggest you give it a shot. Whats the worst that could happen if the sensor doesn't work anyways???
Feel free to ask me any questions if you need to.