Had starter gone over w/new solenoid. Now it will keep spinning after starting some times. Shop says bad key switch or relay that powers solenoid. I changed relay, so with a probe w/ light I check power on coil side of relay. I drops off like it should w/ key. The contact side stays hot when it keeps spinning. This is my new relay, so I tap it no change . Tap solenoid and it stops, power gone on contact side. There is no way for power to back feed right? I can see solenoid sticking but not sure why I see power on contact side. But tapping makes no change, only on starter. Thanks for any ideas.
Your problem is in the starter. When the main contacts in the solenoid on the starter are engaged battery voltage can back feed through the solenoids coil back to the relay's starter side contact connection.
Thanks mg2361. I was thinking on those lines but did not think it could pick up a voltage in the winding.