My daughter is home from college. I notice that when she turns the key on her 2004 Nissan Pathfinder there is one lone click. When she released the key and turns it again, the car starts normally.
This is pretty consistent behavior. Nothing spins, turns or attempts to crank on the first try. She doesn’t do anything different before the second attempt (no fiddling with the brake or transmission lever).
Any thoughts as to whether I should start by replacing the starter or is this more likely a relay somewhere?
Is the click from the starter motor? If so, could be the solenoid is going bad. The contacts inside it can be replaced, or at least cleaned up. But first check battery connections and condition of battery. If this is the original battery, it owes you no more service.
Do the dash lights come on at the first attempt to start? If not, that suggests a problem with the ignition switch.
Yes, I agree, either the battery, or the battery contacts, or the selenoid contacts are the most likely. Usually a bad selenoid contact means replacing the starter motor though, as the contacts are part of the motor. Most retail auto parts stores will test your battery for free with a load test.
There’s other potential causes too, like you mention, sometimes there is a starter relay under the dashboard which can fail, or the ignition switch could be bad. Usually a mechanic wouldn’t just start replacing things. He’d measure the voltages at the starter terminals during attempted cranking and work backwards from there.
That’s true @texases about the Toyota solenoid contacts often being replaceable. I’ve replaced the starter solenoid contacts on my early 90’s Corolla a couple of times. They are part of the starter motor, but a replaceable part. Saved me some dough doing it that way. Ray has said on the show that starter motors are a common complaint on Toyotas. But I wonder if many mechanics would replace the contacts if the contacts were bad? I expect they’d usually just replace the starter motor, and let the rebuilders replace the contacts for the next starter motor rebuild buyer.
It would be too much of a liability for a shop/mechanic to merely replace the contacts, when the starter drive or the solenoid itself might fail one month later.
Agreed with db4690. There’s also the issue of worn brushes, bushings, and commutator which could have been part or all of the reason for a contact failure.