Key ignition problem - Can't shut off
 

My girlfriend has a 1992 Buick Park Avenue and there's a problem with the ignition switch. The vehicle can't be shut off because the key won't turn back. Only way to get it after many attempts is by clicking forward. No good as the starter engages and the engine is already running!

Her ignition key has the "chip" resistor built into it. Dealership quoted around $300 to fix. Locksmith $65 just to look at it. For a quick fix I decided to install a kill switch on the ECM fuse $10 dollars. That allows the engine to be killed, and then gives time to work with the key without engaging the starter.

Sometimes we just have to leave the key in the vehicle. A few dash lights still stay on, but don't think it would drain the battery. What do you recommend to get this fixed. I'm mechanically inclined, and can do the job with some information.

Because it gets quite involved removing wires for the pass key feature plus air bag system plus special tools are required, I would suggest having someone with the tools and experience replace the key tumbler assembly. Do it once, do it right , and it will be done. This is one job that is best left to someone with the right tools and know-how. Wish I could be more helpful, but this is one of those jobs best not to tackle.
You might ask the locksmith if he does this type of work, some do, and at least get an estimate of his charge.

The key tumbler being the main unit for which the key is placed into? Wondering because the locksmith said it could be something mechanical further back into the steering wheel assembly. The battery died, and was tested as no good. New battery replaced under Die Hard warranty. Girlfriend says the ignition seems to be working fine now. Could low voltage have caused this issue?

I would think not. The key tumbler turning can be done with any key cut to fit the original key , but without the coded key the engine usually will crank but will not start.
Anything is possible, if it works now ,great!