Join Date: Mar 2001
Location: Cody, Wy
Feedback Score: 0 reviews
Impossible to say by looking at a monitor. It could be anything from corroded contacts in the starter solenoid (mounted on the starter), a bad segment on the commutator, shot starter brushes, to bad cable connections, corroded batt terminals, mis-adjusted neutral switch if you have an auto trans, etc. Those relays DO frequently fail compared to the other components, that's why I said it was a good chance it was your problem, if not, time to look elsewhere.
Heavy truck and diesel mechanic (thankfully retired after 30+ yrs)
'91 F-250 SC 4X4, 5spd. ATS Turbo, 3:55 diff.