I have 1999 XLT F-150 4.6 Triton v8, and have started running to some serious problems. When i turn the key literally nothing happens. I'm getting battery power to lights, but not the starter. I've replaced the battery, starter, and solenoid. I can start it by using a screwdriver on the solenoid so that pretty much narrowed it down the the ignition. I bought a new ignition cylinder, however i did not know my original key had a security chip so that did nothing. Basically I'm just wondering if there is a way to figure out if its the cylinder, ignition switch, or the entire assembly?

 

Could be a problem with the security system. Does the theft light flash?

 

Only if I use the non-coded key/ignition cylinder

 

Did you check if you are getting power to the starter?

 

He said he can start the truck with a screw driver over the starter solenoid

 

I recommend taking a good look at your battery cables also. I had a battery cable that looked fine but ended up being the issue. It was intermittent. Flexing it one direction and everything was fine. Flex it the other direction and it wouldn't start. Anyway troubleshooting the start circuit was problematic and unreliable because of it.

 

So when you turn the key the solenoid wont even click? If thats the case trace the small post wire on top. It isnt signaling for some reason.

 

I would also check the ignition cylinder. It is easy to pull out and inspect for visible damage like burned contacts. Low cost to replace.