I got one for you.

[4speedfunk]

2006 H3 AT trans...160k miles. Key gets stuck in the ignition tumbler...but starts fine. I can shut the motor off but, I cannot shut the power off. The key will not turn back to "lock" and will not come out of the tumbler. So the ACC is on and the radio, fan, and such are all stuck on. I must take the cowling off the column and remove the passlock solenoid from them tumbler, and then I can turn the key back to lock and pull it out. Good battery. Good voltage.

Here's the weird thing. The shifter can be put into any gear at any time...with the vehicle running or not...with the key in it or not. It can also be pulled in or out of Park without touching the brake pedal. Its like the shifter is not even connected to the ignition system. Passlock light is on but, starts fine. Anybody ever had shifter issues? I'm stumped.

 

[rascole]

I have had several gremlins like that recently. Will be looking at the BCM next, has been years since water intrusion but may have finally caught up to me.

 

[CaseyS]

I have a starting place for you.

The shift lock solenoid is energized to let you shift out of park. So that means the shift solenoid must be powered. Also I believe you can't turn the key off unless you are on park and possibly in neutral. Sounds like a problem with the park position switch. Truck thinks you are NOT in park so you can't shut the truck off and it has no need to deenergize the shift solenoid to hold you in park because it doesn't think you are there. Does it let you start? There are two separate circuits for the park. One is in the start circuit and I think the other goes to the BCM.

Possible things to troubleshoot: shift position quadrant on the side of the trans. Fuses. Chaffed wires. BCM.

 

[4speedfunk]

I think you’re right….it’s something to do with the shifter. I got a new one coming this week. I think the “park” lock has been broken.

 

[rascole]

Wow, excellent diagnosis Casey. I had a similar issue after my sons truck was recovered. Everything powered up but no start. After hours of troubleshooting, it was the shift position sensor, hot wiring it caused a short. 15 minute fix. Hope that is the problem.

 

[4speedfunk]

It magically fixed itself. Started the truck…ran it for five minutes. Now the passlock light is off and the shifter locks into PARK position, and releases with the brake pedal…just like it’s supposed to. Weird.

It’s worth mentioning that I was doing work inside the console. I did press the PARK override button (tow truck guys know about it) to move the shifter, so I could remove the top console plate. I assumed simple cycling of the ignition key on/off would reset the override…wrong. Due to major (SAS) surgery I was unable to start the motor at that time.

A couple days later, I filled the PS system, and started the truck. That’s when the shifter started working again. So I guess you must actually start the motor to reset the tow-truck button.

 

[H3Hummer]

Glad for You 4speed, just an other bad GM part to change

 

[Jeepwalker]

A lot of funky electrical issues (H3 and other vehicles), the *root cause* is a weak battery, poor grounds, and/or lousy terminals. It doesn't seem like a weak electrical path would cause it, but it is often the root problem.

I chased some wierd electrical gremlins for a few years. So did the previous owner. I replaced the batt terminals (which were lousy aftermarkets) with quality solder-on terminals. That helped but didn't completely solve the issue. Wasn't till I replaced the battery and re-seated grounds ...and I discovered a really rusty ground connection under the driver's feet (below the carpet) and have been completely problem free for a few years now. No other items have been replaced. If ya frequent other truck forums, you'll find other vehicles exhibit a bevy of wonky head-scratching issues caused by poor electrical. Worth looking into. A parts store can do a free batt load test, which is a good place to start.

 

[08H3]

It’s worth mentioning that I was doing work inside the console. I did press the PARK override button (tow truck guys know about it) to move the shifter.....

Not directly related to 4Speeds original question, but if you don't know about this, Google it. Either that or make sure you don't put it in Park if you ever lose power. I made that mistake once. Thank goodness for YouTube helping me quickly figure it out while sitting alongside the road.

 

[4speedfunk]

UPDATE
Its been a couple weeks since all this went down. The problem would come & go with no warning, and every time it happened I would have to un-plug the tumbler solenoid to turn the ignition off, and release the key.

On a hunch, I purchased a used 80k mile shifter assembly from a wrecked 09 H3T. Thought I would swap out the whole shifter mechanism, as this complete replacement shifter was a fraction of the cost of just the park switch itself...plus I got the feeling that the entire shifter was very worn. Swapping the shifter was incredibly easy...ten minutes start to finish. Once I got the old one out (160k miles), I compared the two shifters side-by-side. The old one had a lot of friction in the thumb button, and it was rather loose and clunky. There is a spring-loaded pin inside the shifter handle, and this piece seemed to "stick" and not return all the way back to its resting position. The replacement shifter was in much better condition, and worked with noticeably less effort. Once installed, the problems immediately went away...and they have stayed away for at least 30 start-stop cycles. So I'm going to call this one "fixed".

In summary...don't start knee-jerk replacing of expensive electronic do-dads. Even though the problem manifested itself in pass-lock lights, stuck-keys, service 4WD, and a host of other dash lights...the real problem was a worn and gummed-up shifter. Easy fix.

 

[06 H3]

Sometimes the shifter button sticks and doesn’t release all the way and causes issues