So I had to replace my Ignition cylinder and and as soon as I did that I wasn't able to start the truck unless I pushed on the steering wheel i hear a buzz and it starts no theft light. it did this for about 2 weeks and yesterday I tried to start it in the same fashion and it wouldn't start finally it started but every time I try turn the truck off I have to go through the same procedure. So I took the Ignition cylinder out consider out because there are 2 wires coming from the housing I believe they're white and black and if I wiggle that around The truck will start. However, that must have tripped the PATS and Now it won't start at all. Once it cycles through the initial alarm (lights and horn) the theft light just blinks every 4 to 5 seconds . If i get out of the car and then I open the drivers side door it sets of the alarm I'm not able to lock the doors automatically anymore but if I insert the new key into the ignition cylinder and turn on and off after 9x foong this thr locks engage on the doors which is supposed to reset PATS but still does the same thing alarm goes off then theft light blinks every 4-5 seconds theft light not Giving off a one-2 or 3 core ... I still have the old key but I thought the 1998 does not have a chipped key
Please help!!! I work on it myself and am the original owner so I know the truck pretty well but this has me stumped

 

Welcome to the forum

In 1998 PATS was optional, pay extra, and if you don't have a Chipped key then you do not have PATS

You have an Alarm system it sounds like, PATS is "passive" anti-theft, not an alarm
Alarm systems also have a flashing dash light to warn thieves of the alarm system

Why did you have to replace the cylinder?
If it was because if was getting hard to turn then you have an Ignition Switch issue or its actuator rod, in and under the steering column

Alarm systems are usually activated or deactivated by key in the drivers door, or via Fob, not ignition key
Alarm is to prevent entry but will usually have a starter deactivation relay somewhere if alarm is "tripped"

If alarm is not tripped and key doesn't activate starter then I would think you have an issue with actuator rod or ignition switch, especially if you moving the steering wheel allows startup

Simple diagram of what happens when you turn the key: https://www.corvetteforum.com/forums...h-photo753.jpg

Key turns a gear and the actuator rod moves
Actuator rod is connected to the ignition switch under steering column above brake pedal, looks like this: https://i.ytimg.com/vi/KK2uO_xaDKA/maxresdefault.jpg
The silver post in picture is then moved into its 4 positions, ACC, OFF, RUN, START

If actuator rod or gear is damaged then key can be hard to turn or won't always pull ignition switch all the way to START position

 

I also replaced the ignition switch and had a,hard time with getting it lined up with the rod so I will check that tonight... thanks for the quick reply appreciate your suggestion

 

Try operating the ignition switch when its not bolted in place, its just a Slide switch
Disconnect battery when working on electrics, always
Pull out switch and plug it back in
Hook up battery
Transmission in PARK!!!
If it starts engine each time, then it is not an alarm issue

 

It's a manual tranny ... the ignition switch I can feel it clicking into accessory, off. Run and start but when I turn the key to start and try to start it nothing no click just nothing ... battery has enough power to crank the engine it's like no power to the starter... fuse is good relay is good ... but what effect would pushing on the steering wheel have that would make it activate the starter?

 

The ignition switch is under the steering column above brake pedal

The key turns a gear that pushes/pulls the Actuator rod that moves the ignition switch into its 4 positions, ACC, OFF, RUN, START

Pushing on steering wheel may be pushing actuator rod just enough to engage START on ignition switch

Simple diagram of how ALL keys on steering columns work: https://cimg7.ibsrv.net/gimg/www.for...e1343a526d.gif

And here: https://www.fixya.com/uploads/images...0_08_36_pm.gif

Key cylinder itself has no wires, ignition switch has all the wires, key just moves the gear and slides actuator rod

 

There are 2 wires from the lock cylinder housing white/green and either black/white or brown/white that are connected with a plastic tab that has a metal piece inside the housing that buys up against the lock cylinder I could wiggle these then had to push up on steering wheel then it might start... now it's not starting clicking or doing anything at all... I'm curious what these 2 wires are for

 

Could be an ignition tamper switch, seen in this drawing: https://f01.justanswer.com/gEsic6fP/...48e55ef7c1.png

Below is 1997 anti-theft wiring, 1998 should be the same
green/white and black/white wires

Looks to be a ground but thru a resistor in its "normal"/untampered position
The resistor value is not shown, so simply cutting and twisting the wires together is not a option, this was a popular method to prevent "hot wiring" ignition switches on motorcycles
You could test the wires with OHM Meter to get resistor value, then get matching value resistor to bypass the switch/sensor

If this switch/sensor has failed then that could prevent start up even if alarm was not activated
But same switch/sensor would be on many many Fords 1995-1999 or so, wrecking yard pick, I doubt Ford Dealer would have one, but free to call and ask, its called "Ignition switch tamper sensor"