How can I detect a Low Jack Tracking device place on my vehicle?

First its not a good idea to piggyback your question on someone else's. Especially when you question has nothing to do with the other thread. This can lead to confusion. You should start a new thread. So I've moved your question to its own thread.

I would take it to a dealer and ask them to check.

They are mounted at various places, if you are looking for the actual unit and normally have some fail safes to disable the car if removed improperly.
So you will need to check with your dealer or the local lo jack dealer to have work done to it.

As for as seeing the signal, you would need a receiver like the police have in many of their cars.