Turn igintion switch on engine won't start - 2001 Mercury Sable

try to clean both side of the key where the little resistor (some people call it chip)with rubbing alcohol
or try your spare key
you can check the resistor with DVOM (digital volt,ohm meter)
put black lid on one side and red on the other side while set on ohm or kilo ohm
if it shows it is open ,you need new key
don't let lock smith guy or dealer say it need to programmed
find the right value of resistance and get on eBay

all it is, just resistor to complete the vat circuit,and tell pcm to send the voltage to your starter solenoid

Has anyone checked to see if you have power at the starter when the key switch is in the start position ?
Could be several things including the battery, cables, starter, neutral safety switch, or key switch.

Sounds like a blown ignition switch. check all fuses first then looks like you may be replacing a switch. BUT it comes as two different pieces. A mechanical lock cylinder and the electrical pigtail that mounts to the back. You will be replacing the electrical pigtail for the ignition switch

check all your fuse under bonnet or under driver or passenger compartment site.i like to know if you have immobilizer alarm in your car.

Are you saying the engine cranks but won't start, or the engine won't crank ?
If the engine does not crank, you would check for voltage at the starter, the neutral safety switch, and the key switch as well as the ground connections.

Try this procedure:
Check the battery like this:
Turn on the headlights, then try to start the car.
If the headlights do not dim or go out, then the battery is likely ok.
Check that the battery cable plus post, goes to the starter, Minus post to a good ground, like the engine.
If wiring is ok, then look at the starter solenoid for a good connection, and proper voltage at the starter.
Problem is most likely the Solenoid's bendix gear or starting relay, Have someone bang on the starter while you try to start the car. This usually works by dislodging the bendix gear..
Hope this helps.

do you have spark? I believe that model has an an igintion control model but would need motor size for better clarification. If you have spark, your timing is good. Sounds more like a fuel pump or clogged fuel filter. Check your fuel rail under the hood. Did it just not start one day or while driving or something else?

ricks63toy, I believe that Ford still uses what is called an inertia switch even in the hybrids. This switch will shut off in the event of an accident shutting off the fuel pump. This is a safety feature built into the vehicle. Seeing that this is a newer vehicle I trust that you still have the manual. If not, the switches are usually located in the trunk. Look on the side walls of the trunk and see if you can locate it. It is usually marked by a sticker. When you find the switch, push the red button down until you hear a click. This will reset the switch and allow power back to your fuel pump. Good luck with this.

if the sterring wheel is in the locked possion try pulling the wheel very hard to either the right or left while trying to turn the key

Check the starter solenoid, or igintion switch