I have a 2004 Monte carlo SS, 3.8 vin K. A couple of days ago my recirculate on my A/C stopped working. I can still select the fresh air or recirculate button, but the fan does not speed up and you can't hear any difference. I saw online it may be the Service Module Valve Actuator. How can I find / replace this piece? I located what I think is the correct part AC Delco 15-74123 but I can't find out where its located in my car. Do I need to remove the whole dash to get to it?