1996 Toyota Previa van chirping sound what could the cause be We just had the supercharger pulley replaced and the belts replace within the last month and now the chirping is more frequent and louder?

Other possibilities could be one of the the accessory belt idler pulleys - either the one that connects to the accessory driveshaft bracket, or the one that connects to the A/C compressor bracket. If the bearing has gone bad, it would likely produce a chirping/squealing noise. Another thought is the accessory driveshaft coupling, which is a common problem in the Previa vehicles. It consists of two round, rubber pieces that act as a support/damper between the accessory driveshaft. The rubber eventually wears out and deteriorates, which will lead to noise and vibration. Another idea is the alternator ... have you checked that out to see if the chirping sound could be due to worn alternator bearings? Or if the belt tension is too tight, that could be putting more stress on the shaft and bearings, increasing the frequency/volume of noise. If you have a mechanic's stethoscope, it would come in handy for locating/diagnosing noises such as chirps, squeals, etc. Good luck!