Mine works about 50% in Park. It works 100% in neutral so that's the backup plan. I'm not certain but it seems to me there are different length switches. You might also have a bad switch. I'd check the year the trans was built and get a switch for that year and compare to what you have. O'Reily and Autozone carry them. Some shifters have neutral switches built into them too. I don't use them as I like the tranny switch, it seems more durable and accurate!