There are three IOD fuses, and one main IOD fuse.
The main one is in the white holder in the fuse box. Look at the fuse to make sure it's not blown. Pull up on the holder to raise the fuse, then push down, making sure the fuse is reseated.
The other three are M10, M11, and M13. Make sure they are not blown.
If all is well there, here is some info for the U0184 code:
U0184-LOST COMMUNICATION WITH RADIO
With the ignition on.
Battery voltage between 10 and 16 volts.
IOD fuse installed.
TIPM is configured correctly.
Set Condition: Bus messages not received from the Radio for approximately 2 to 5 seconds.
CAN C INTERIOR BUS (125K) CIRCUITS OPEN OR SHORTED
DTCS RELATED TO BATTERY VOLTAGE, IGNITION, OR VIN MESSAGES
TIPM NOT CONFIGURED CORRECTLY
RADIO POWER AND GROUND
MODULE THAT SET THIS DTC
2008 Unlimited Rubicon Automatic