Because it's difficult to give a precise visual description without seeing the specific vehicle, you might need to consult a repair manual specific to your 2006 Jeep Grand Cherokee's year, make, model, and transmission type. A service manual will provide diagrams and exact locations. You can also search online for images of "2006 Jeep Grand Cherokee neutral safety switch location" to find pictures from other owners who've accessed this part.
Caution: Working on the transmission can be complex. If you're not comfortable working on your car yourself, it's best to take it to a qualified mechanic.
