Where is the grounding strap located on a 2000 Jeep Grand Cherokee?

There are grounding straps everywhere on cars and trucks. Begin by looking at the battery. The posts have cables coming from the (+) and (-) terminals. The (+) side has a cable that goes to the starter, solenoid and fuse box. This cable - and the wires connected to it - are insulated and never touches the vehicle frame, body or exposed metal. The (-) cable however is securely fastened to the engine - usually near the starter or other convenient, easy to access location. Additionally, there are copper jumpers or straps that extend from the (-) post to the exposed metal portions of vehicle frame, body panels, dashboard, etc. This provides a path for the (-)12 volts and ensures it is available everywhere on the vehicle with out the need to run a separate (1) wire to each location that has a (+) wire.

Copper is used as it is a better conductor and more flexible than steel. You should be able to connect one lead from a 12 volt test light to the (+) 12 volt battery post and the touch the other lead anywhere on the car that is metal and light the lamp. If the lamp fails to light or lights only dimly - it because the metal isn't connected to the (-) 12 volt side of the battery due to a missing ground strap or because of a poor or rusty steel connection. Placing one or more straps between metal that provides a bright test light and the metal section that provides a dim or no light at all will make the light glow brightly.