Hi guys have a simple question here,does the spring on the under side off the hood latch that bolts to the rad support keep tension on the hood release cable.

Yes there is a small return spring on the latch mechanism that is bolted to the radiator support panel. This spring returns the latch to a locked position (and therefore pulls the cable) when you release the cabin bonnet release lever.

Yes. What he said. The end of the cable engages with the latch mechanism and locks in. Very similar to cable connections on bicycle brake levers for your handlebars

See Bonnet, latch section