South Texas Health System McAllen 301 W. Expressway 83 McAllen, Texas 78503 Hours: Monday - Friday, 8:00 am - 4:30 pm Phone: 956-632-4076 Fax: 956-289-2964. South Texas Health System Edinburg 1102 W. Trenton Rd. Edinburg, Texas 78539 Hours: Monday - Friday, 8:00 am - 4:30 pm Phone: 956-388-6642 Fax: 956-289-2964.