i wish i had more customers as wonderfully desciptive as you are. while the 'groung' wire problem is a possibility, i think it unlikely w/o other symptoms. there are 2 ways to go here, throw a dart [at the 'diagnositc dart board'] or troubleshoot the problem each with a cost/benefit factor. i always use the later but the pre-condition is that 98% of the time, the symptom MUST be present. to eliminate everything BUT the starter motor [which do fail! ] your technician must access the 'starter circuit' harness connection located in the 'E-box' below the fuse panel. this easy to access and if the 'large' black/yellow wire has within 0.5 volts of B+ while the key is in 'crank', the starter is defective. IF NOT, the problem is further back in the switch, EWS, trans. interlock, etc... BEST of fortune to you....................jb.