I just purchased a 1998 Cherokee today, does the ignition key operate the tailgate lock ? Thanks

it should yes. My lock is broken and never used it but other jeeps i tried work. Usually if the ignition was changed the cheap way the key will work for the ignition but the locks you have to use another key. Typically the original jeep key that came with yours from factory unless they changed all the locks for that key as well. What is your lock doing? Because i have yet to fix mine but mine refuses to move since someone tried breaking into my jeep and proceeded to hammer a screwdriver into it and failed. Thus rendering mine broken but works with the remote locks.

Yup