I’m occasionally having problems with my ’07 Chevy Cobalt (with automatic transmission) where it will get stuck in Park. When I press the release button on the gear shift, a loud click is audible from beneath the steering column, and it remains locked in Park as if I had forgotten to press the brakes. When it works correctly, I don’t hear the same click (there may be a softer click but it’s hard to tell if it isn’t just the physical click of the release button).
Once, while the gear shift was working, I also noticed that when I shifted back into Park, the car doors didn’t automatically unlock as they usually do. At another point in time, they did unlock, but with an unusual delay.
Searching for this finds a lot of questions about people with similar symptoms, but who also cannot remove their key from the ignition. I have never experienced that. Since this seems to be related to the feature that prevents you from moving out of Park without your foot on the brakes, I checked and determined that the brake lights do work correctly when the brake pedal is pressed.
Searching also suggests—but I’m not at all certain—that the culprit for the refusal to shift out of Park is likely the “shift interlock solenoid,” which is plugged in under the gear shift (and distinct, as I understand it, from the “shifter solenoid,” which is also attached to the gear shift and controls the actual shifting of gears, and has totally different symptoms when it starts to go). I haven’t been able to find good information about the auto-unlock feature, whether that’s more symptoms of the same problem or a symptom of some other problem. Also, the fact that the loud click seems to be coming from under the steering column rather than under the gear shift has me worried that the failure is actually in the solenoid that’s under there, instead. But my understanding is that if that were failing, the brake lights wouldn’t work, and they haven’t shown any trouble.
Unfortunately, the ’07 Cobalt does not have a shift interlock override, as many other (newer?) models do, so I can’t test if that’s the problem by using the override. The only advice in the manual about it is to take it to the dealer. This is a very old car that we’re trying to replace (and don’t expect much of anything in trade-in value anyway), so I really don’t want to invest more into this if I don’t have to.
So, does anyone know (or have strong, backed-up suspicions of) what’s causing this, whether that’s the shift interlock solenoid or something else? My assumption is the two problems are related but if that’s wrong, I’d definitely like to know (the shifting issue is far more serious than the auto-unlock). I’d also definitely appreciate pictures of the part I need, and instructions for doing the replacement (if it is reasonably user-serviceable, which the shift interlock solenoid appears to be), if that’d be possible.