Disc brake squeaking starts with high temperatures on the face of the pad and then it is magnified at the back of the pads where they contact the caliper. When you replaced the brake pads did you have the rotors machined? You should because the run-out on the rotors can be part of the problem. Also you have anti-rattle clips; were they installed correctly? If you did these correctly then try this: Remove the brake pads and on the back of the pads apply a couple of heavy beads of RTV silicone and let it set up for 20 minutes then install the pads; that should take care of the noise.
The brake pedal has a hinge or pivot pin, give it a shot of lubricant,should stop squeaking.
Warped brake rotors. This is a very common problem for the 1999-2004 Grand Cherokees. You will need to have your rotors replaced, or resurfaced. The best resurface method is with an on car brake lathe.
Brake rotors or drums need to be machined or replaced. If it causes steering wheel shaking, check front brakes. If happens when applying parking brake look to rear brake problem.
The pulley has probably gone bad. This is very common for Caravans. Try having the pulley replaced and see if that solves the problem.
Problem?
Sounds like a brake wear indicator. If it changes while braking then it is. Recommend a brake inspection.
I had the same problem, all I did was replace the fitting that the bulb goes in with a new one ( $8.00 fix) and replaced the tail light and haven't had a problem since.
Problem with the brake switch, below the pedal. The mounting may have got bent keeping them on.
Couple of things. Check the ground for the loom at the rear. If that is clean and tight I would suspect that the problem is in the brake light switch.
Usually they are just used to prevent brake noise (squeaking etc.) I was told that the shims should be used to set space tolerances between pads and rotor, if so, at what measurement? I have no idea!
catlytic converter is plugged and needs replaced
The brake pads might not be adjusted properly. The brake pads can be too tight and have contact with the rotors.