5.25"
Most roof racks have a total capacity or around 165 pounds.
check the fuses
I have a 1999 Grand Cherokee with the standard roof bars, the maximum limit recommended in the owners manual is 68Kg or 150ibs.
If you have a Cherokee from 1984-1996 with speakers that would have gone in the tailgate, then if you take off the interior tailgate panel (be careful not to break any clips!) and the wiring should be behind it. Just install your new speakers and replace the interior tailgate panel. If you have a Cherokee from 1997-2001 with speakers that would have gone in the ceiling, then take down the headliner temporarily and wiring will be in the roof. It's probably easiest to get a soundbar off of eBay or at your local junkyard and install the bracket and soundbar in the factory location, then connect the wires to the speakers in the soundbar. There is always rear speaker wire going from the radio in the front to speakers in the rear.
If you do not have a sunroof, check/reseal the bolts that hold the luggage rack down.
their are nutcerts in your roof. which use Allen head type srews. the Allen screws go through your roof rail and screw in. be sure not to over torque them. it can stripp your nutcerts.
Opening a sun roof on a jeep is easy. All you have to do is unlatch the roof from the jeep and push the open button.
the deck/roof enclosure just pops out with gentle prying around the egdes after that its a matter of getting the right size/ohm rated speakers and wiring harness adapters to make it goof proof, you may have to drill some holes if the mount holes don't line up, most aftermarket speakers use 4 mounting holes and oem use two on that model. but it isn't really all that hard to do.
the sunroof motor is located in the roof about 3/4 of the way back there is a bump in the headliner drop the headliner and it is easy to find
It wasn't thrown off, but on the roof. Cherokee children would take a tooth they lost and throw it on the roof while saying 4 times "Beaver, put a new tooth in my jaw."
Above your rearview mirror there should be a small black 'ball' (extending from the roof of the car). That is your module. If it's not there, I'm not sure if your Jeep has it. You can always refer to the owner's manual (you can snag one from eBay cheap if you don't already have it) or drop by your Jeep dealership to have them find out for you. Hope this helps!
on what car???