First off details on my truck: 2007 Silverado 1500 LTZ Extended Cab (new body style) Black on Black (I love it!) Z71 4x4 2K Miles First off, I LOVE this truck. Everything about it. Well until this. I have a Garmin C340 portable GPS that I love. I bought it late last year and it has saved me a few times. Well today I plug it up to look for a certain store and all of a sudden the windshield washer fluid starts flowing from the wipers. The wipers move and all just like if I were to have been holding the toggle down. I first saw this about a month ago but didn't know wtf was going on. I didn't relate it to the GPS at all. It kinda worried me but I didn't pursue it as it only happened for about 20 seconds and didn't happen again. Well today as soon as I plugged the GPS in it happened again. So I reached down and unplugged it and magically the wipers stopped! I plugged it back in and it did it again! So I thought maybe it was an electrical issue and my GPS has a battery backup so I kept it unplugged but turned on GPS on battery and once again it did it. It runs for like 20-30 seconds then stops. About a minute later it will clean my windshield again but just for 2-3 wipes and then it doesn't do it anymore. So I know it isn't just an electrical issue with the outlet I am using. I suppose it causes some sort of interference with the computers somehow and I think once it detects it's satellites the wipers stop. Also to note - I do not have automatic wipers. I know the Dual Cab's do and so do some of the SUV's but my truck does not. I also don't think this happens every time I use the GPS. I know this has only happened twice and I am pretty sure I have used my GPS more than twice in this truck. It is just annoying to no end. Has anyone ever heard of this? Any ideas as to if I should complain to Chevy or Garmin?