If your '05 is same as my '07, there is a "roll off" switch located in one of the throttle cables, just in front of the front gas tank bolt. I't's a two prong connector. Even without cruise, one of the wires is hot, and may be shorting against something. If it's not that, start looking at all of your cruise control wiring (I hope you have a serv. manual) for shorts.
Here's a pic of the connector.
Another thing to help find it is pull everything that covers the wiring harness for that circuit and visually as well as feel each individual wire for cracks, abrasions, and abnormal alities. Shake the wires and watch for the light to pop back on. That should help you out as well as verified all the connections are solid.