diff --git a/fermipy/diffuse/gt_merge_srcmaps.py b/fermipy/diffuse/gt_merge_srcmaps.py
index <HASH>..<HASH> 100755
--- a/fermipy/diffuse/gt_merge_srcmaps.py
+++ b/fermipy/diffuse/gt_merge_srcmaps.py
@@ -102,7 +102,8 @@ class GtMergeSourceMaps(object):
         for source_name in source_names:
             try:
                 source = source_factory.releaseSource(source_name)
-                like.addSource(source)
+                # EAC, add the source directly to the model
+                like.logLike.addSource(source)
                 srcs_to_merge.append(source_name)
             except KeyError:
                 missing_sources.append(source_name)
Speed up gt_merge_srcmaps.py by adding source directly to c++ likelihood object