It is easy to do with online instructions. Just google "2004 Jeep remote programming"
You might need to programming the remote. Their should be instructions in the users manual. You're remote could also be need new batteries.
I had the same problem. Google "keyless entry remote 2003 Jeep Grand Cherokee".
The only way to program keyless entry is with a very expensive diagnostic tool called "Launch" or go to nearest dealer for programming.
To reprogram a 2004 Jeep Grand Cherokee keyless entry remote, insert the key into the ignition and turn it to the "On" position without starting the engine. Press and hold the "Unlock" button on the driver's door while simultaneously pressing the "Lock" button on the remote. Release both buttons, and then press the "Lock" button on the remote again. The locks should cycle to confirm successful programming; if not, repeat the steps.
You have to program it with a DRB (Scan tool).
dealer has to do it with factory scan tool
To reprogram a 2000 Jeep Grand Cherokee keyless entry remote, first, insert the key into the ignition and turn it to the "On" position without starting the engine. Within 10 seconds, turn the key to the "Off" position and back to "On" three times, ending in the "On" position. After a chime sounds, press any button on the remote to program it. Repeat this step for additional remotes, then turn the ignition to "Off" to exit programming mode.
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!
Remote start was not available on a 1999 Jeep.
A programmed RKE fob (remote) or a chipped key is required.
You need a remote start system that works with the alarm/smart key system. You can not just unhook the alarm.