'06 Trailblazer ignition problems

[mytrailblazersucks]

I have an '06 Trailblazer that is having ignition problems. Sometimes it will start up fine and others it won't start at all. I turn the key and all the instument lights come on and the radio comes on, but the car won't crank. My husband changed the ignition switch, and that did not help. We seem to think it might have something to do with the factory anti-theft system. A mechanic my husband knows told him to see if he can get a new ignition cylinder and change that. Anyone have any ideas before we go spend alot of money? Thank You

[maxwedge]

Welcome to AF, guess you are out of warranty here? Anyway there is a relay under the hood that activates the starter solenoid, the BCM sees the ign key turned on and closes that relay, lots of systems in place here. I don't think it is the ign key cylinder here, but electrical checks with a wiring diagram must be done when the condition occurs, this is not a " guesswork" repair.

[mytrailblazersucks]

Thanks for the reply. We took it to a dealer this morning and had it looked at. It is the computer, which had to be replaced. There is no more warranty due to mileage, so we had to pay. They assured us this would fix the problem, and the new computer has a 12 month, 12,000 mile warranty. It just sucks that this is a manufacturing problem and we have to pay for it. It has nothing to do with wear and tear of the vehicle.

[maxwedge]

The computer (pcm) is warranted for 8 years or 80k miles, unless it was the bcm?

[mytrailblazersucks]

You know what, that's almost funny! It was the pcm and the truck has a little over 81,000 miles on it. My husband works out of town and has to travel alot. He drove it for a year back and forth to work and then decided to give it to me and get a truck. Oh well that's how things work out sometimes.