I have been looking for a thread that mite help but have been unable to find any thing useful...

I have a 03 tahoe LS that has some issue's at the moment.... every thing controlled by the PS door quit working ( i,e window,lock's,seat heater,door lam switch.... ect.. ) I have been searching for a loose ground or a faulty ground but have not been able to find any thing that would cause this.
I have talked to a few shops in town and they all say it happen's a lot and they get them like that all the time but they will not tell me what it is or where it is... just that they will fix it for 400 buck's...

thanks for the help... if there is a thread on this topic please point me to it....