I will second the corrosion bit. Had that issue on mine as delivered. The terminals they used to connect to the battery positive were simply THE WRONG STUFF.. I ultimately fixed, took me 9 years but I fixed :)
YOu have both a relay and a solenoid, The relay makes a "CLICK" sound if it's not making contact, The CLUNK is the solenoid
The relay is in the main chassis fuse box and is the bottom right relay.
HOW DO I KNOW THIS..... Happened Monday last.. Figured it out and got er working no cost.. YIPPIE My favorite repair bill $0.00.