Superduty won't start
 

I have a 99 F-250 superduty w/7.3 L Diesel. Without anywarning of a start problem I tried to start last might with no response, not even so much as a click from a relay. i have checked the batteries and they are both good. There is no corrosion on the terminal posts. I have looked at the cables and there looks like there could be a little corrosion on the inside of the positive cable near the primary battery. Can anyone help me figure out what could be worng (starter? cables? something else?)?

Check fuses,then grounds.

Forgot to mention that part. I have looked at the grounds and the fuses. All seems to be good.

Starter has 2 circuits. One circuit is the starter control for crank and terminate commands. The other is the high power cranking circuit that does the work during engine startup.

There should be voltage at the large battery cable to the starter all the time (same as battery voltage). If not, then you are not getting power to the starter high power cranking circuit.

With the key switch in the start position, check for roughly 12V volts at the starter solenoid switch terminal. If not, then the problem is somewhere in the control circuit and not the starter.

If those pass then replace the starter or have it repaired.

Radio, dash lights, gauges, etc. coming on or no?

Auto or manual? Have you tried starting in neutral instead of park?

Thanks for all of your replys/suggestions. So here is the update. everything checks out and I tried to start in Neutral with success. When I turned off I tried again in Park and it started again. A few moments later I tried again in Park and it would do anythin again. I think there is a shift lock that prevent the truck from starting when not in Neutral of Park. I am assuming that this is what is the problem. Does anyone know how to fix this?

Look up under the dash where the lever connects and there should be a couple of torx head screws. See if they've come loose. Sometimes tightening them down will fix this issue. Otherwise it seems like there's an adjustment somewhere on the linkage to check.

i have a 99 thats doin the same thing, intermitently wont start in park but if i crank it down to 2nd or 1st then shove it back up to park itll turn over no problem also sometimes when i put it in park like if im parking at a store or something the mechanism that keeps the vehicle from rolling back too far doesn't engage and i'll start rolling back but the motor idles as if it is in park, go figure i guess got to adjust something. oh yeah and it wont drop into first anymore, somethings gotta be wore out, idk.