battery is good, dash lights up all lights and door locks work.

 

Because not all vehicles, models or even years are the same , Need to know ;
Year
Model
Engine- if known
Do you have a second key, if so ,
try the other key. Could be a security system problem.

 

2005 sport trac 4.ol ,no crank no start

 

What did you try?

 

checked the keys, security system is good, pulled fuses, checked all grounds, new battery, new starter. Sometimes it will start for 3 days then nothing.

 

Can we ask how you determined the security system was good ?

 

I did a few recommended test. why would the truck sporadically start if the system was shut down. Any and all help here is appreciated, I've been on this thing for 2weeks.

 

The functionality of your vehicle's security system is contained in the PCM. Starter is disabled when there is a problem.
What does the anti-theft light do when it will not start ?
Is it on then flashing or on solid for 60 seconds ?
When it would not crank over, you did try the other key , Yes/No ?

 

P.o re rd wea ccx sQUOTE=hanky;119999]The functionality of your vehicle's security system is contained in the PCM. Starter is disabled when there is a problem.
What does the anti-theft light do when it will not start ?
Is it on then flashing or on solid for 60 seconds ?
When it would not crank over, you did try the other key , Yes/No ?[/QUOTE]
yes on the key. Solid for 3sec. then goes out. checked starter wire at ignition, shows power when trying to start.

 

OK , from the start wire at the sw. it should go down to the sw on the side/top of the trans MLPS (Manual lever position sw) formally neutral safety sw. if automatic, if std shift , to clutch safety sw. from there to starter sol on starter.