Every once in a while when my my son tries to start his car ( Usually when it has sat for more then 10 hours) He only gets a 'click' he attempts to Start the car a few times and finally the Starter kicks in. Right off, I'm thinking the Starter is going bad but I was wondering if the Starter Relay can 'switch' (so that's the Click he hears)but be dirty or old enough not to send power to the Starter Solenoid? He just cleaned the Battery Terminals when this started happening..no change. I will have him clean the wires on the Starter as well as the Relay. I guess next time it does it, I can have him Hot Wire directly across the Starter to see is it spins up or still Clicks. When the car does Crank, it is a strong Turn, not like the Starter is laboring.
Replace the relay first?