Upvote:1
The Christian Kingdoms of Spain were at intermittent wars with the Muslims and also with each other (e.g. see Timeline of the Muslim presence in the Iberian Peninsula which contains dates of major battles and wars). In addition, unlike France and England who could come up with some sort of truce while they went on Crusade, I don't think the Muslims of Spain would have granted any truce to respect their Christian rivals going on Crusade.
Therefore, sending their leaders and warriors across the sea to fight someone else's war would have been a suicidal move for these kingdoms.
Upvote:4
There wasn't much Spain to speak of until later, and the Spaniards were already crusading in Spain before, during, and after what's usually referred to as the Crusades:
(gif via http://www.newworldencyclopedia.org/entry/Reconquista)
The last Muslim stronghold, Granada, fell in 1492 - the same year Columbus discovered America, putting the Age of Discovery in full motion and shifting the focus away from controlling the Levant.