On my 02 cc sb d/a. They work sometimes and then all of a sudden they won't. after awhile, they start working again. Another thing that happened on saturday is right after the door locks started working, the next time that I started the pickup, the illumination for the gear selector on the instrument cluster didn't work. It came back on after driving for about 5 minutes. Does anyone have any ideas what might be causing? It all started on saturday. the pickup runs great and this is the first problem that I have ever had with it in 63,000 miles.
any and all advice and recommendations are very appreciated.

Welcome to my small club, my rear doors won't unlock all winter and sometimes after a rain. It's been to the shop about 5 times for this issue. Started around 20K and still does it at 56k. Every module has been replaced twice and the wiring harness has been looked at many times. I have pretty much given up hope for the locks, reach thru and unlock them by hand.

Does yours happen all of the time? Mine acts like it has a loose connection. They won't work for 5 or 10 minutes and then all of a sudden you'll be going down the road and they lock on their own. It's weird.

Does yours happen all of the time? Mine acts like it has a loose connection. They won't work for 5 or 10 minutes and then all of a sudden you'll be going down the road and they lock on their own. It's weird.
they lock on their own?

maybe the switch is bad?

This is the nsbu switch on the alli that is going bad take it to stealer and get it fixed under warranty// bet you can't get it into 4w lo when it acts up either// been there it will limp you into 3rd gear one of these days and these trucks don't like running at speed in 3rd..

dollyo11 - Thanks. I will check the NSBU switch in the morning. I do not have any factory warranty left on my pickup. Can anyone tell me if they will go ahead and fix it or should I just buy the part and do it myself?

marksrt43 - It's not that they lock on their own: it's that they quit working altogether.
The reason that they lock on their own while driving is because when whatever it is starts working, the auto lock function kicks in and locks the doors.

One other question. If I take my pickup to the stealer for this, do I need to take off the K&N intake system first?

Well I went to the dealer here in Dumas this morning armed with all of the info from this site (thanks guys). I thought that I was ready for anything that they threw at me concerning the NSBU switch. WRONG!!!
First, I had to spend 45 minutes arguing with the service manager that it is in fact a warranty item on the dmax.
Then, after waiting another 45 minutes, the service manager and the head mechanic who was working on my pickup, came out and told me that they could not duplicate the problem so that they could check it out. I asked if the door locks had started working again since they had quit on me on the drive to their shop. I was told by themechanic that they were not working but that the're are not connected to the NSBU switch. I told them that they WERE connected to it and that all I wanted was for them to change the d@mn switch. He went back to the pickup for about 10 minutes and then came back and told me that he ahd traced out the wires and they did not go to the NSBU switch.
I told him fine, just give me the keys and I would take it somewhere else. He then gives the keys to my pickup to the service manager who tells me that he would get this added up and have me out of there in no time ( I don't think that they liked me).
I aske dhim what he was "adding up" and he told me the charges and taxes for 1 hours labor working on the door locks. well at this point I just freaked. After the @ss chewing that I gave him,his mechanic, their manager, the owner of the dealership, and any customers that were in there thinking about buying a car from them, I was kindly told that I could leave and not to worry about the $45.00 charge.
I then drove home, called a different dealership in Amarillo, Tx (45 miles away) and asked to speak with the service manager there.
When they got on the phone, I told them what the pickup was doing and the first words out of their mouth was, " it sounds like the NSBU switch to me". I told them what the other mechanic had said about the door locks not being connected to the switch and the guy told me that evidently that mechanic had never heard of a computer. I made an appointment for tomorrow morning in amarillo after I get off work so I will have to see if this guy is as good as his word.
Sorry about the rant but it just irritates me when you spend alot of money investing in a pickup like this and then GM hires idiots to work on them.
On the lighter side, while I was standing at the service counter in my work clothes since I had just gotten off work, a lady that worked there came up and asked me if I had any "goodies' on my pickup. I started listing the intake, nerf bars, bed rails, and other items. I noticed she had this strange look on her face and I stopped and asked her who she thought that I was. She said, " aren't you driving the Schwann's truck parked outside?"
I guess men and women DO have different ideas about what "goodies" are.

David, the nsbu switch is covered under the federal emissions warranty for 5yrs or 100k miles.. Page 20 in your light duty truck warranty book// good luck just got my money back from the replacement of mine// a good dealer will know this info//mine is in the shop now for injectors told dealer about my prob with nsbu and he said that's covered so I guess you need to ask if they know what a dmax is before you take it to them//

after alot of arguing, I did get them to look it up and agree that it was a warranty repair. I just couldn't get them to change it.