trying to fix it on his own. This is a 2003 F350 Diesel Powerstroke 4x4 used primarily to haul horses around the region. For the last several months, we’ve had intermittent episodes of it hesitating to start (glow plugs heat up, truck “sighs”, complete the turn on the ignition switch and it would pause a couple seconds before the starter would engage. Once, this was due to a loose starter, and for a while after the starter was resecured, this problem stopped. It also seemed to happen more with cold starts. Ultimately this problem escalated from delayed start to not starting at all until “something magic” happened, and we’d try the key and away it would go. This is problem #1.
The second part of this is my DH, who wants to be handy but lacks tools and expertise, wanted to address this himself and was adamant that we couldn’t take it to the Ford dealership for diagnosis and repair. This led to a 20 yo son, in frustration, taking a vice grip to the ignition thinking if he could only turn it a little further…it would start (he was late for a practice for the second time and frustrated). I also think he errantly believed that his dad would NOT tackle fixing the ignition by himself. (Has he not met the guy???).
Ignition replaced. Truck started twice, once to get to a practice, and once to get home. Now, it has been sitting with the hood up looking very neglected for a week and the house I live in is awash in male ego bumping. Periodically we go turn the key to see if the stars are aligned correctly or the fairies have sprinkled happy dust on it, to no avail. Husband is more obsessed with fixing it (because now we would have to pay to tow it to the dealership). I have become unwilling to let him do more to it without skilled supervision.
Goal: 1. reliable vehicle that starts when ingition is turned to “on” – every time.
2. Not having air bag spontaneously deploy while I’m driving because some wires were misaligned during the home ignition repair (can this happen???)
3. A husband who stops talking to himself with a faraway look in his eye, scanning the Chiltons and growing more grizzled everyday “…maybe it’s the relay. That’s it…I’ll try a new relay…”
To summarize: truck and egos intact.
Go to a Radio Shack or equiv. and get a $10-20 multi meter.
Set it to read DC volts.
Have one person turn the key while another checks the voltage between the ground terminal of the battery and the thin wire to the starter solenoid (near or on the starter.)
If there is no voltage there it’s probably the wire from the ignition switch or a relay.
If voltage is there it’s probably the solenoid.
The Dad here, is there a starter relay and if so where is it? The location in the diagram is inaccurate, I can’t find any relay on the passenger side of the engine compartment… Is there not a starter relay on this vehicle?
Not going gently into that goodnight.
The Dad
Yes. There is a starter relay. It’s located at the central junction box behind the lower left of the dash.
Tester
Ok starter relay in the central junction box, little black four prong unit, starter solenoid relay is mounted in the engine compartment or is it on the starter motor?, I’ve followed the three wires from the passenger side battery one leads to the glowplug relay on top of the engine, The main line appears to run uninterrupted to the starter motor (one heavy line then a smaller ground). Third line runs to the other battery.
Less hair then when I started,
The Dad
The relay is in the the box, the starter solenoid is mounted on the starter.
Tester
Many thanks, dealership sold me a relay switch that isn’t part of my system. I spent a good hour (or more) looking for a relay that mounts on the right fender well. I pulled the starter and went to disconnect the power and the connection on the top of the solenoid fell off in my hand. Took the unit back to non dealer part store got my free replacement starter and solenoid. installed it in 2o minutes. Truck started right up. A short touchdown dance followed by a couple choruses of “I fixed the truck, I fixed the Truck” later my wife had to acknowledge the value of my perseverance.
Thanks again.
Except for a few natural mechanics,most of us went through this sort of thing when we started working on cars. You learn one step at a time.
And it was a cute dance, too. 
Thanks for persevering and getting it solved. Want to tackle the leaky faucet under the bedroom window next? <<>>
Yes, and when we have time, we’ll practice reading the wiring diagrams and chasing wires and circuits with that new, handy, dandy, digital multimeter … just in case we run into another little electrical problem, won’t we?