2004 Hummer H2 S Hummer During Rainy Drive Windshield Wipers Stopped About 1

"It's a 2004 H2 Hummer. During a rainy drive the windshield wipers stopped about 1/3 their way up from the park position. I pulled them to the upper most point in the cycle and they completed the cycle to the far extreme and returned to the park position but that's all. If I turn them on and then off I can pull them up in the same way and they stay there until I turn them back on at which time they again advance to their far extreme and return to the park position and stay there. If I turn the on and LEAVE THEM ON and I pull them to the upper position (or thereabouts) they go to their far extreme on their own and return to the park position. And finally, when I turn them on I hear a mild 'clicking' noise. I've check fuses (I think all of them) and wiggled wires etc. I've read about a 'breaker' but don't see one. Thanks, Tom.