diff --git a/scripts/lib/CIME/case/preview_namelists.py b/scripts/lib/CIME/case/preview_namelists.py
index 2c588293ff6..90addfe06ed 100644
--- a/scripts/lib/CIME/case/preview_namelists.py
+++ b/scripts/lib/CIME/case/preview_namelists.py
@@ -4,7 +4,7 @@
 """
 
 from CIME.XML.standard_module_setup import *
-from CIME.utils import run_sub_or_cmd, safe_copy
+from CIME.utils import import_and_run_sub_or_cmd, safe_copy
 import time, glob
 logger = logging.getLogger(__name__)
 
@@ -77,17 +77,10 @@ def create_namelists(self, component=None):
         else:
             compname = self.get_value("COMP_{}".format(model_str.upper()))
         if component is None or component == model_str or compname=="ufsatm":
-            # first look in the case SourceMods directory
-            cmd = os.path.join(caseroot, "SourceMods", "src."+compname, "buildnml")
-            if os.path.isfile(cmd):
-                logger.warning("\nWARNING: Using local buildnml file {}\n".format(cmd))
-            else:
-                # otherwise look in the component config_dir
-                cmd = os.path.join(config_dir, "buildnml")
-            expect(os.path.isfile(cmd), "Could not find buildnml file for component {}".format(compname))
+            cmd = os.path.join(config_dir, "buildnml")
             logger.info("Create namelist for component {}".format(compname))
-            run_sub_or_cmd(cmd, (caseroot), "buildnml",
-                           (self, caseroot, compname), case=self)
+            import_and_run_sub_or_cmd(cmd, (caseroot), "buildnml",
+                           (self, caseroot, compname), config_dir, compname, case=self)
 
         logger.debug("Finished creating component namelists, component {} models = {}".format(component, models))
 
diff --git a/scripts/lib/CIME/utils.py b/scripts/lib/CIME/utils.py
index 398f19776a1..4bc320b6426 100644
--- a/scripts/lib/CIME/utils.py
+++ b/scripts/lib/CIME/utils.py
@@ -422,6 +422,28 @@ def file_contains_python_function(filepath, funcname):
 
     return has_function
 
+def import_and_run_sub_or_cmd(cmd, cmdargs, subname, subargs, config_dir, compname,
+                              logfile=None, case=None, from_dir=None, timeout=None):
+    sys_path_old = sys.path
+    sys.path.insert(1, config_dir)
+    try:
+        mod = importlib.import_module(f"{compname}_cime_py")
+        getattr(mod, subname)(*subargs)
+    except (ModuleNotFoundError, AttributeError) as _:
+        # * ModuleNotFoundError if importlib can not find module,
+        # * AttributeError if importlib finds the module but
+        #   {subname} is not defined in the module
+        expect(os.path.isfile(cmd), f"Could not find {subname} file for component {compname}")
+        run_sub_or_cmd(cmd, cmdargs, subname, subargs, logfile, case, from_dir, timeout)
+    except Exception:
+        if logfile:
+            with open(logfile, "a") as log_fd:
+                log_fd.write(str(sys.exc_info()[1]))
+            expect(False, "{} FAILED, cat {}".format(cmd, logfile))
+        else:
+            raise
+    sys.path = sys_path_old
+
 def run_sub_or_cmd(cmd, cmdargs, subname, subargs, logfile=None, case=None,
                    from_dir=None, timeout=None):
     """