A month ago, my husband noticed that some caps on some of the hoses in our 2007 Prius are apparently missing. We had a smog test done several months ago and possibly the missing caps may be related to that. Regardless, we want to replace the caps but we don't know what they are called. Also, we have developed a problem where our heater now blows cold air only. We don't know if this problem is related to the missing caps. We have tried fully filling the coolant reservoir and bleeding out any air bubbles but that did not resolve the cold air situation. We plan to try replacing the thermostat next but we want to deal with the missing caps first in case the recent heater problem is related. 2007 Prius
Those caps are dust protection for the high and low pressure test connections on the AC system. Should also have a flexible seal inside to act as a semi-backup to the test fitting if it has a slight leak, but they're not exactly reliable as a pressure boundary. You should be able to run down to any NAPA or decent parts store and purchase them. They're pretty standard between manufacturers.
