A couple of general points about an A/C add in.
1. Take out the entire dash of both vehicles and switch over every bracket, duct and both HVAC boxes. Include the wiring harness as the HVAC vacuum supply lines are included.
2. Drink copius amounts of beer.
3. The heater water valve is different.
4. Drink more beer.
5. When installing A/C replace EVERY stinking 'O' ring because you need to upgrade to 134.
6. Drink more beer.
7. Install a NEW, that's right NEW accumulator - dryer assembly. This will help when recharging the system to have dry 134 and weeks from now you won't have to be concerned with mixing oils.
8. Drink more beer, go on the internet and purchase an XJ already equipped with AC. I wish I had because it would have been easier and less frustrating than the 'upgrade' modification.