To short out or not to short!!!!!! Help

[dr.olds]

hey its me again, my 02 silerado is doing some weird stuff,short mabe, as i was driving noticed volt guage flucuating,also gear selector and odometer light flickering, when i would tap on the brake pedel volt guage would discharge for a split second ond go back to where it was suposed to be and the radio would turn off and would come right back on same thing thing would happen when i would roll a window down (power windows) I tried evey button and switch in the truck to try to narrow it down, when i would turn something on it would discharge but not as much as brake or windows and the radio would not go off! got almost home and it quit hasnt done it since! Im lost! Ground problem mabe? need help, would like to find it before it really gets bad! thanks Eddie.:cool:

[DickWells]

Just noticed this. Have you fixed it yet? Sounds a bit familiar. Have you checked the PRNDL, or whatever it's called, thingy on the left-rear of the transmission? It's known to mess up all kinds of electronic stuff on the DM-ALY. Go back through the archives here and you'll find the right acronym for it, and a bunch of info. Water incursion, is what they blame for the problems. The left-front tire will throw water back onto that connector in a left turn. The new units have a better seal. Sorry I can't be more specific, because I never can remember the right acronym for that block. Mine's light brown in color, I think the older units were black.

[cowboywildbill]

It could be a bad ground or like Dick said it might be the netraul safety switch.
If it turns out to be the switch, you can by it from an allison Dealer for under a $100.
I think I paid $50.00 for mine several years ago for our 02 GMC.
I know the GM Dealers get about $250.00 for the same part.

[dr.olds]

turns out it was bad batteries, both of them went bad at the same time, replaced, and all is well, thanks for the advise, about water in the box from the tires in a left turn, or was it a right turn? and the netral saftey switch, could be very useful info for the future! thanks, Eddie:cool:

[mastertech]

just for thoes that do not know. if you disconnect one battery on a duramax and try to start it and it does not crank them the battery that is hooked up is no good repeat to the other one an dyou can check both of them and see wat one has low cca with out having to go out and buy a tester