IIRC there is a difference in the type of communications between those years.
That sounds like a question for Mike @Wranglerfix ; he is the resident ECM technician...
It should run but will not control the gauges. You can use a 97-98 Cherokee and I can make it a Wrangler. 4.0 auto or manual. What is the part number on your 99?
My dad's CB handle was The Peddler...As long as it's a good working unit I'll work a trade for you, sir.