At first I thought it was passlock but Security light not blinking. Now when I turn key I hear a hum from engine comparment (fuel pump?) for 5 secs, instrument panel lights up, then when switch to "on" it stops and all the intrument cluster goes blank. Thinking ingition swith? check fuses all look okay. Engines does not crank.

 

Passlock has nothing to do with the starter, it prevents fuel from being injected.
Ignition switch is a possiblity but I would check the battery first. It may be able to run the fuel pump (the hum you hear) but not put out enough amps for the starter.
Next look at the battery cables, especially the positive one, for corrosion, including under the protective boots. Then check the cables to the starter.

 

Thanks for the response. Did check battery. Car will sometimes turn over. I'm thinkning switch based on you additional thoughts. Seems key has to be just right. Problem is inconsistently an issue. difficult to really determine problem. Question, If I change the switch should key cylinder be replaced as well.

 

I would just change the switch.

 

Today the weather in the 60's car started everytime I tried. this cant be temperature related can it?

 

Any chance you were using a different key? Sometimes an old, worn down key can cause issues with the switches.
I doubt it's temp related, but I have seen stranger things...

 

Put new ignition switch in today. Car started right up. We will see. Like I said problem has be intermittent. Cross my fingers. Key does feel better in ignition though. no play. Thanks for the help.

 

oh and yes we have two keys and they both caused the same issue.

 

I've got to replace the ignition switch in my 2001 alero. Did you have to remove the entire panel/console in the front? I wasn't sure how to do this.

I've got a similar problem, I turn the key to the "on" position, and I can hear the fuel pump, but when I turn the key over, it won't start. It won't even crank - BUT only when it is cold outside. No problems at all when the engine or outside temp is warm. I'm not sure my switch is bad, but at this point, I've replaced the batter, positive cable, starter solenoid and park safety switch...

 

You'll need to remove gear shift cover, radio console cover and radio, and instrument cluster. This allows you to get to the three screws that hold the ingnition switch in place. I'm fairly handy and it took me 2 hours, half hour looking for screw I dropped in gear shift compartment.
Instructions I followed:
http://wiki.answers.com/Q/How_do_you...dsmobile_Alero

Good luck.