How serious is it when the VSS wire is cut?
 

Like many people here, I've added a factory nav/radio head unit to my 07 nbs silverado 1500. I had some problems at first with getting voice prompts, but once the vss wire was tapped into correctly, it was working like a charm. Last weekend I added a rear view camera, and that was smooth sailing, but then I noticed that the voice prompts had stopped working again and I had lost the navigation functionality of the unit. I figured that meant the vss tap had come loose or the wire had come loose from the brown connector behind the radio itself. I checked the connection on the floor first (much easier to get to) and I found that the original vss wire tap wasn't very good. The VSS wire (green with white stripe) had been cut and the green wire from behind radio was just kinda wrapped around and barely holding it all together. How serious is it that the wire has been completely cut? I tried just twisting the three ends together and they just don't all reach. Can I splice any wire to the ends to make them longer? Do I need to use a specific matching gauge or anything? I think the box on the floor, up and to the left of the brake pedal is called the mbec (maybe) you have to unhook it and flip it over to get to the vss wire. There looks to be like a hundred or so wires all twisted up, are they each connected to something? It seems like they're just twisted up tight and out of the way?

any wire will do. try to get some solder on the connections so they never come loose again

Thanks Shawnvw! I actually took my truck in to a car audio place today and they did a real nice job soldering the wires together and used shrink tubing to cover the connection. I gave it a nice tug and it felt really secure. Problem is, I'm still not getting any voice prompts and about 80% of the time the north dial points to the left no matter what direction I'm driving and when I make a turn, in stead of the map turning and it looking like the truck icon is always facing and driving up, the icon will be facing up but moving right on the screen, as if I was driving sideways. Any ideas what would cause this? I know it all worked fine before the rear view camera was installed, but we didn't change any of the nav wiring during the camera install. Not sure if you've read any of my previous posts, but I'm not sure my radio has been programmed. I took to the dealer twice to have the theft lock removed and to program with a vin relearn as per many of your posts, but the dealer said they were unable to learn my vin or program my radio, because parts were missing. After I had the VSS wire tapped into correctly (on the underside of the floor box) everythnig seemed to worked so I never took it back for programming. Could this be what I need to do? Someone told me if everything is working than it's programmed. What do you say Shawnvw? Thanks, I really just want this thing to work already!!!

If the radio turns on, then the VIN is learned, if all audoi and function operate properly, then no programming needed.
You problem sounds like the VSS is missing from the radio. how is the wire connected at the back of the radio?

thanks shawnvw, i was thinking i needed to take my truck back to the dealer, glad that i don't. As far as the wire behind the stereo, it came attached to a brown connector in pin 5 i think. I pulled the radio out today and it was in there pretty snug. The supplied wire is fished behind the dash and is now soldered into the vss wire on the back of the floor junction box. The wire HAS to be cut or crimped or something somewhere along it's path. Maybe it got snagged on something behind the dash when we pulled the radio out to add the camera connections. I'm not sure, but it seems to be connected at the vss wire and at the back of the radio, so it should be working. If it hadn't worked before the camera was installed, I would think the unit was defective, but it had all worked before. Thanks again!!!