Manual Transmission problems of the 2003 Volkswagen GTI

I have taken my '03 Gti vr6 to the dealer 3 times for the same complaint. When it is raining, there is a squealing noise coming from the passenger side of the car. Dealer could not replicate the problem each time I brought the car to them. They said that it could be the belt but it would not be covered under warranty. I replaced the belt myself and I still get the squealing noise, even with belt dressing. I have also noticed a decrease in engine power when the squealing noise is occurring. My most recent problem now is my speedometer and fuel gauge stop working intermittently. The speedo will be reading my current speed and then drop to zero, bounce back up and back down to zero, up a little bit more and then stay at zero until the next time I drive the car. Seems to do this only on trips greater than 20 minutes.