Doors won't unlock

[chrisinkanata]

We just got back from a trip to Daytona for the 500 last weekend. About 5500 trouble free kilometers except the door locks. I noticed that when the truck is put into park, the doors do not unlock. You have to do it manually. Also, the 'P' in the gear selector is not highlighted in park. In all other selections, no problem and the doors lock as normal when going from Park to drive. I live in eastern Ontario (lots of snow, salt and corrosion), so could this be related to the neutural safety switch? Is that how the body module senses to unlock the doors?

Thanks,

Chris
Kanata ON

[More Power]

There's a "Park" switch in the steering column that tells the rest of the system when the shift lever is in the park position. That switch might be at fault, and is likely the cause of your door lock problem.

Our Lil Red (http://www.thedieselpage.com/features/project2-16.htm) Duramax conversion is using the original 1989 steering column, which doesn't have the park switch. The "P" isn't illuminated when the truck is shifted to park because of that. No downside otherwise, but I'm not using the auto door lock function. :)

Jim

[Kennedy]

I'd look at the NSBU switch on the transmission also. Could be an adjustment issue, or just a bad switch.