Try turning bluetooth off, turning your iPhone off, turning off the bletuth device you are attempting to connect. one by one, power on the iPhone, then once the iPhone is fully powered on, turn on bluetooth, then power on the device. If that procedure does solve this problem, here is a link for troubleshooting this kind of thing - Apple - Support - Bluetooth
Yeah, Nelson, I agree with KiltedTim - make sure you put the devices into pairing mode. To do this with the Jabra Cruiser, start with the unit turned ON, then press and hold the answer/end button until you hear the voice indicate, "Pairing mode." Once in this mode, try turning ON Bluetooth in your iPhone - it'll start a search right away and should find the Cruiser.