Okay, so it's a 98 GMC Jimmy, with 240k miles on it. The motor was swapped at about 200k and it now has about 170k on it. The Trans was literally just replaced with 90k miles on it.

So I'm having a problem with the ignition cylinder not turning to off. It will turn to "on" where my dash lights up and shuts down the motor. It doesn't turn to off to let me pull the key out. Can't disconnect the battery cuz the key will be stuck anyway.. I'm baffled because I've never had this problem with any other blazer variant I've had..

 

There are three major components/functions to the "ignition switch". First is the lock cylinder which houses the tumbler and pins for the key. As a minimum this has failed in your case and can be replaced on its own. Here is the procedure:



Then there are the electronic functions. When the key is rotated to the different positions power is routed to the vehicle systems and eventually to the starter circuit. Lastly, there is a resistor value presented to the passlock system in run to tell the BCM to power the fuel injector pulses. Replacement of the electronic portion requires passlock programming or the resistor hack, both relatively simple affairs.You may or may not have an electronic problem, I can't tell from your description but you definitely have a lock tumbler or key issue.


George

 

My first guess would be that the shift linkage is out of adjustment and not letting the shifter go completely to "park". Just a guess, though.

Always suspect the last thing that was worked on before the problem occurred. In this case, it sounds like that was the transmission.

 

This is an even better idea which I had completely missed. I would start here instead.


George

 

I readjusted the Shift linkage this morning. What all on the trans affects the ignition cylinder other than shift linkage. I will definitely tinker with the shift linkage again before I go messing with electronics.

Though I can confirm that it shift fully into park (only because I've climbed under, unhooked the linkage and pushed it into park. It was where it was supposed to be)

Thanks for the help so far, I will slowly make the rounds rounds test everything that is being posted.

 

1) Not fully in park as discussed
2) Steering wheel is locked and up against the stops
3) Bad ignition tumbler as I mentioned earlier
4) Worn key
5) Dirt in the cylinder

Try moving the steering wheel back and forth while you try to remove the key. Wiggle the key up/down, in/out, pull out slightly then try turning. Sounds like you have a handle on the shift being in park already. It may still need that new tumbler assembly after all this


George

 

Thank you very much, George. I will be sure to run down through that list before I go and replace anything. If all else fails, I'll buy the part and put it on. Not my first rodeo replacing ignition stuff. Much appreciated.

 

Replaced pretty much everything but nothing worked. I did figure out the issue though. The shift cable was still not set in the right position. I have to wiggle the shifter a little and it comes out

 

Glad you got it sorted.


George

 

Glad the initial problem was solved, Zee. I wanted to throw out some other basic items to check for others who read this very common issue with Blazers/Jimmy's. Check the key to see if it is bent or damaged in any way. My key is long and tends to bend. Try cleaning it with rubbing alcohol. If you have several copies of the key, try those. Some times the original key will work and the copy won't. If so, get some new copies made at a key shop and see if they work. Good luck, and remember a new key copy from Home depot or other is cheaper than a new cylinder lock or a new SUV !