I have a 2004 John Deere 240 Skid Steer. The Port Locks 7.5am fuse keeps blowing especially when I try to move forward/back or engage the foot pedals. I have checked all of the wiring and cannot find any shorts. Is it possible the solenoids that engage the port locks are defective? If I just have the engine idle with the parking brake off it does not blow the fuse. Appreciate any help.