I agree!!! I have the 5.7L and the problem was the "slave solenoid". It's
a $20 part located just above the fuel filter next to the red ignition
circuit breaker button. . The clicking noise is the copper disk engaging
the contact points when pushed by the solenoid but the copper disk is all
corroded and does not make good contact. Don't bother trying to take it
apart and cleaning it.....just buy a new one. It's a real simple install.




I'm not sure about a 5.7l, but my 7.4l has an intermediate solenoid,
located
right next to the 30 amp circuit breaker on the engine, on the left side,
front, over the water separator filter. Mine went bad- it was
intermittent,
but there was no click at all when it didn't work. Not nearly expensive a
part- I *think* it was about $20.