Some 2005 Jeep Liberty, Cherokee and Wrangler models with 3.7- or 4-liter engines may intermittently illuminate the 4WD light on the dash when in 2WD mode.
In some cases, the Check Engine light may also be on, with trouble code P0573 (brake switch #1 circuit high) stored in computer memory.
According to Chrysler, if there are no drivability issues associated with the illuminated warning lights they're probably bogus and caused by software gremlins in the PCM. Updating the module with updated software is the only surefire fix. Check with a dealer for the specifics of the flash.