Neighbor has a 2002 Ford Explorer. About three weeks ago it ‘ate’ a starter relay - one of the black cans in the box on the driver’s fender.
Replaced it, it ran fine for three weeks. HOWEVER, this week, owner drove it about 7 miles to work and parked - and it wouldn’t crank, same exact symptom as before.
What do I need to do to confirm that there is not a further problem with the starter/bendix/solenoid? I don’t just want to go put new relays oin it and have this happen in another three weeks.
A bad or corroded starter lead to the battery will make the starter try to pull power through the relay. Double check the connections and even run a voltage drop test on the main starter lead to the battery.
Over 25 years I owned 2 Galaxies, 4 Mustangs, 1 Lincoln, and a Crown Victoria. I learned early on to keep a new starter relay and appropriate tools in the glove box. I only replaced 2 batteries, 1 starter, and 1 set of cables. I don’t think I have enough fingers and toes to count the number of starter relays replaced. I always thought it was just an inherent defect.
There’s a number of reasons why the starter may not engage; even intermittently. A faulty relay is not high on the list.
Battery, battery cable connections, starter motor itself, ignition switch, range selector switch, starter interrupter relay if the truck has a security system, etc. are some of the possibilities.
Check for 12VDC at the starter wires when the key is in START. If you have the voltage, it’s either the starter motor itself that’s intermittent or (sob) the starter motor gear isn’t engaging, preventing the contacts in the bendix assembly from closing and enabling the starter motor circuit.