I am having a problem with my VW Beetle, the AC was woring great Monday night and Tuesday morning when I started to work the AC will not come on at all. The dealer tells me it is either the fan or a coolant Module, can someone give me some advise or tell me where this module is located so I can try to check it or change it myself, the dealer wants 250.00 to replace this part. Thank you for your help in advanced..