diff --git a/pypeit/core/wavecal/autoid.py b/pypeit/core/wavecal/autoid.py
index 334c3223fe..f36d9d4e6b 100644
--- a/pypeit/core/wavecal/autoid.py
+++ b/pypeit/core/wavecal/autoid.py
@@ -1053,6 +1053,10 @@ def full_template(spec, lamps, par, ok_mask, det, binspectral, nsnippet=2, slit_
 
     # Load template
     if template_dict is None:
+        # Error checking
+        if par['reid_arxiv'] is None:
+            msgs.error('WavelengthSolutionPar parameter `reid_arxiv` not '
+                       'specified for "full_template" method.')
         temp_wv, temp_spec, temp_bin = waveio.load_template(
             par['reid_arxiv'], det, wvrng=par['wvrng_arxiv'])
     else:
diff --git a/pypeit/core/wavecal/waveio.py b/pypeit/core/wavecal/waveio.py
index e765ebe90a..5760d72907 100644
--- a/pypeit/core/wavecal/waveio.py
+++ b/pypeit/core/wavecal/waveio.py
@@ -50,7 +50,7 @@ def load_wavelength_calibration(filename: pathlib.Path) -> dict:
     return wv_calib
 
 
-def load_template(arxiv_file, det, wvrng=None):
+def load_template(arxiv_file:str, det:int, wvrng:list=None)->tuple[np.ndarray,np.ndarray,int]:
     """
     Load a full template file from disk
 
@@ -73,13 +73,8 @@ def load_template(arxiv_file, det, wvrng=None):
         binning of the template arc spectrum
 
     """
-    # Path already included?
-    if pathlib.Path(arxiv_file).name == arxiv_file:
-        calibfile, _ = data.get_reid_arxiv_filepath(arxiv_file)
-    else:
-        calibfile = pathlib.Path(arxiv_file)
-    # Read me
-    tbl = astropy.table.Table.read(calibfile, format='fits')
+    calibfile, fmt = data.get_reid_arxiv_filepath(arxiv_file)
+    tbl = astropy.table.Table.read(calibfile, format=fmt)
     # Parse on detector?
     if 'det' in tbl.keys():
         idx = np.where(tbl['det'].data & 2**det)[0]
diff --git a/pypeit/data/utils.py b/pypeit/data/utils.py
index 263eb52872..cba62b0153 100644
--- a/pypeit/data/utils.py
+++ b/pypeit/data/utils.py
@@ -211,18 +211,30 @@ def get_reid_arxiv_filepath(arxiv_file: str) -> tuple[pathlib.Path, str]:
     version of PypeIt).
 
     Args:
-        arxiv_file (str):
+        arxiv_file (:obj:`str`):
           The base filename of the ``reid_arxiv`` file to be located
 
     Returns:
         tuple: The full path and whether the path is in the cache:
 
-           * reid_path (:obj:`pathlib.Path`): The full path to the ``reid_arxiv`` file
+           * reid_path (:obj:`~pathlib.Path`): The full path to the ``reid_arxiv`` file
            * arxiv_fmt (:obj:`str`): The extension of the ``reid_arxiv`` file (format)
     """
-    # Full path within the package data structure:
+    # First check that what is passed in works
+    if not isinstance(arxiv_file, (str, pathlib.Path)):
+        msgs.error(f"Incorrect or non-existent arxiv file specified: {arxiv_file}")
+    if isinstance(arxiv_file, pathlib.Path):
+        arxiv_file = str(arxiv_file)
+
+    # Check if the `arxiv_file` already comes with a full path
+    if (reid_path := pathlib.Path(arxiv_file)).name != arxiv_file:
+        # Check existence, return it with format
+        if not reid_path.is_file():
+            msgs.error(f"Incorrect or non-existent arxiv file specified: {reid_path}")
+        return reid_path, reid_path.suffix.replace('.','').lower()
+
+    # Else, full path within the package data structure:
     reid_path = Paths.reid_arxiv / arxiv_file
-    arxiv_fmt = arxiv_file.split(".")[-1].lower()
 
     # Check if the file does NOT exist in the package directory
     # NOTE: This should be the case for all but from-source installations
@@ -235,7 +247,7 @@ def get_reid_arxiv_filepath(arxiv_file: str) -> tuple[pathlib.Path, str]:
         reid_path = fetch_remote_file(arxiv_file, "arc_lines/reid_arxiv")
 
     # Return the path to the `reid_arxiv` file, and the file format
-    return reid_path, arxiv_fmt
+    return reid_path, arxiv_file.split('.')[-1].lower()
 
 
 def get_skisim_filepath(skisim_file: str) -> pathlib.Path: