Hello and welcome to just answer Jeep. I have been researching my diagrams for your 2000 Grand Cherokee, and do not see a common fuse that would supply power to the wipers, headlamps, or tail lights. Now there is a # XXXXX 50 amp fuse in the under hood fuse box that supplies power to the head lamp relay circuits, so check that one. However one thing that is common to these 3 items is the Body Control Module (BCM). It is possible that the BCM has failed and is causing the issues you are having. But before we decide that the BCM is the culprit, check ALL of the fuses with a 12 volt test light. There is an inside fuse box located under the driver's side of the dash to the left of the steering column near the left kick panel. There is a black plastic cover that needs to be removed, and then you will see the fuse/junction block. Try to get a 12 volt test light, connect the light's alligator clip to a good metal ground (metal portion of the dash, bolt, etc.) then probe the little metal tab/test points on each fuse. There will be 2 on each fuse. Probe one tab, on each fuse, and then the other. If the light lights on one tab then it should light on the other tab of the same fuse. If you have light on one tab and not the other, then that fuse is bad. Do the same thing on the under hood fuse box by the right side of the engine compartment. Check this and get back to me. If you do not have a 12 volt test light, then purchase one at your auto parts store (under $10.00).
Hope this information helps, and let me know if you need more assistance with this.
Do the wipers work now?
It may be that you have a poor fuse connection, and when you went to check the fuses you disturbed the connection enough to make it work again. If this problem returns, then go back to the fuse box while leaving the headlamps on, and wiggle fuses to see if you can make them come back on again. It may be a corroded/loose fitting fuse connection.
Thank you for the accept, and I will be here for you if you need me again,