Thereupon, although you did not plan to perform an inspection of the wheel wells, I would suggest you perform one. Inspect if there are any of items. Such as small box or cylinder.
Yet, be alerted that there is a high possibility for the hidden GPS tracker to be placed on the wheels.
Inspecting the Interior of a Vehicle for a Hidden GPS Tracker
Since you performed the exterior inspection so far, now it is time for you to make a detailed inspection of the interior of the vehicle as well.
Do not forget that there can be a hidden GPS tracker in the interior of the vehicle as well! (Although the chances are very much low)
Additionally, you should be alarmed all the time. By that, I refer that you should keep your focus on places where the GPS can be hidden quickly. (Because who can stay for a longer period of time in your car to place one)
After all it is logical. Who can spend a lot of time in your vehicle without you detecting it? (This does not stand for company vehicles.)