Which engine? 3.7 and 4.7 definitely have an IAC and the 5.7 probably does (but I don't know and don't have the FSM in front of me).
On the 4.7 (and I believe the 3.7), it's in basically the same place it's always been, too: On the throttle body right next to the TPS. It's easy to miss it if the resonator's still on, though, which may be why you're not seeing it.
2006 WK Laredo 4x4 4.7L
1993 ZJ Laredo 4x4 4.0L — Dead, sold, and rolling again