02 f250 with 7.3 psd. 4x4. Starter to start rough. Almost like it was cold, but it was 70 °. Had that for two days. Then my dad tries to move it, and it won’t start. No crank. Nothing. I go to orileys and buy one for $250. Install it myself, and nothing. Lights come on. I try moving the column shifter. Nothing. I tried tightening the shifter, still nothing. It is loose when you wiggle the handle but the screws are tight. We pushed it into the garage and I got a warranty off the starter and replaced it. Nothing. I’m still in high school and I take a Diesel Tech class. Told my teacher and he told me to test it by touching the two prongs needed. I did and nothing for a bit, and after touching them a few times together it aced and spun but didn’t engage. A few months ago my dad got me two new batteries from Sams club (Walmart but you buy in bulk) because they were on sale. I pulled all the fuses under the steering wheel and one was blown and I replaced it. Still nothing. I don’t remember which one it was that I replaced. It cranks by hand with a socket and wrench underneath as easy as it should. The first starter I bought didn’t work so I took it out and bench tested it. I remember it engaged and sound one and a while. Then nothing happened, not even a spark. Now still nothing when I try to crank the truck over. It’s my daily driver and I’m just lost at what to do. I’m very hands on and I don’t have the money to pay someone to fix it for me. I’m just desperate.

 

Have you checked the starter relay in the under dash fuse box? The 02 has it in the cab where the earlier trucks had a relay on the passenger fender area. Also ensure your ignition switch is working properly.

Do you get power to the starter? Have you tried it in Neutral? It could be the interlock on the shifter.

 

I was going to say check the interlock on the shifter. You beat me to it! I don't know too much about how the 02 model relay for the starter was set up. My starter relay is on the fender well as you said. Very easy to get to. I would put a volt meter on the starter solenoid wire and see if when you turn the key it tells the starter solenoid to click over. It would be the little red wire going to the starter. Again that's on my truck. I don't know anything about the 02 models. My truck has a solenoid on the fender and on the starter.

 

I have not checked the relays under the dash. I’ve put it in neutral, and every other position it can go in multiple times and doesn’t work.
How would I make sure my ingirion switch is working? And what’s the interlock on the shifter? I’m familiar with the Diesel engines, I can get my way around them pretty well for being pretty young, I’m not not familiar with the electrical side and the non-engine parts.

 

If it is cold where you are try jumping the big lugs on the GPR with a fat screwdriver for 20 seconds, then try to start. This will bypass the GPR and send a lot of amps straight to the glow plugs. Be careful because duh fat amps will scorch you.

Pretty sure the batteries are strong? A way to read voltages and codes would help. Something like Forscan app on your cell with a blue tooth adapter. At rest 12.3v is fine and when cranking with GPs on voltage should not go lower than 10ish.

Is the CEL lit? That means codes are stored.

FWIW the 7.3 is rather different from most diesel engines. This is your opportunity to learn the deep mysteries.

 

Jumping the GPR won't help if the engine doesn't even turn over. That would be the next step once he gets the starter spinning.

 

Cleaned your battery terminals? Are the grounds to the block clean?

 

I would start by checking your battery terminal connections. -Maybe also test with a good set of jumper cables to another vehicle to see if there’s a change.
Then move to checking the power signal at the starter (like Hyakkimaru said).
Both of these are free and should help direct your next steps.

 

Check those batteries, wally world/sams club batteries are junk imho , take them out take them down and have them load tested! I they are not holding 10.2 amps under load they will not turn the 7.3 over

 

^^^^^^ I agree with everything they said about batteries. I had a lot of issues when I first got my truck until I got two new batteries. Also it may seem stupid but, is your shifter linkage actually shifting the transmission in and out of gear when you're moving the gear shifter? I have seen it before. You'll think your putting it in park but it's still in drive. And you said all the lights were still coming on it just wouldn't turn over. Just a thought!

 

A quick way to split the system and see if the problem is with the starter or if it's truck wiring is to jump the starter. On 99 to 01's start by jumping the the posts on the start relay on the passenger side fender. on the 02-03 the quick way is to pull the connector apart on the passenger side fender and touching it to the battery.

The following video is about a 6.0 truck but the starter wiring is the same for the 7.3 02-03 models and it shows the connector. You can skip to about 25 seconds in if you want.

 

Terminals are clean

 

How would I check if it’s shifting the tranny? Thought about the neutral safety switch and testing it, but I have no idea how

 

I will be sure to try that once I get home, thanks

 

Thinking about it now, I did have the idea to check the ground to the block. Just don’t know the location, and haven’t had time