We had the battery on our 2005 Rendezvous replaced for 169.95, which took three trips to the dealer (Kirkland Buick) and found that when we attempted to buy minutes, the technician was unable to install them. Upon checking back with Kirkland Buick, we were told that the On Star module needed to be replaced at a cost of $650.00, which seems excessive. We have another vehicle (Buick Encore)which also has On Star and we have found the service to be a great safety measure when traveling. It would appear that we can no longer use the Rendezvous On Star service due to the excessive cost. Is there a possibility that this is going to happen to our other vehicle sometime in the future? Cynthia B Erickson - John A EricksonPri