We should not infer from this that our desires are not guided by reason. Reason continually guides people without them being aware of its guidance. When we reason or think about the merits of an object, we are regularly directly aware of doing so. To reason or think is to act in a particular way, and a person is normally aware of what he is doing. Using reason does not in itself require performing an action.
People use reason when they rest beliefs on evidence.
Evidence that p is reason to believe p. When people rest beliefs on evidence, they usually do not ponder the evidence. Most people who use telephones believe they have ears. Though this belief is founded in evidence and so guided by reason, few people contemplate the evidence for their having ears. Not all of a person's beliefs are themselves conclusions of other reasoning.