Starter motor solenoid cable

[AMacdonald]

My 2011 1.6 Bluemotion has developed an odd starter fault. It won't crank but the solenoid repeatedly switches. Each time it does, the dash display blanks for a second before it repeats. If I run a cable directly from the battery to the solenoid, it cranks normally. After a bit of head-scratching I think I've decided the solenoid cable must be shorting somewhere along its run but I haven't been able to locate where yet. Does anyone happen to know where the solenoid cable terminates or, even better, have a wiring diagram? My searches have come up empty so far.