diff --git a/C4/Heading.pm b/C4/Heading.pm
index cce3abf6fc..8b8ece8aac 100644
--- a/C4/Heading.pm
+++ b/C4/Heading.pm
@@ -210,34 +210,11 @@ sub _search {
     }
 
     if ( $thesaurus ) {
-    # This is calculated in C4/Heading/MARC21.pm - not used for UNIMARC
-        if ($thesaurus eq 'lcsh') {
-            $subject_heading_thesaurus = 'a';
-        } elsif ($thesaurus eq 'lcac') {
-            $subject_heading_thesaurus = 'b';
-        } elsif ($thesaurus eq 'mesh') {
-            $subject_heading_thesaurus = 'c';
-        } elsif ($thesaurus eq 'nal') {
-            $subject_heading_thesaurus = 'd';
-        } elsif ($thesaurus eq 'notspecified') {
-            $subject_heading_thesaurus = 'n';
-        } elsif ($thesaurus eq 'cash') {
-            $subject_heading_thesaurus = 'k';
-        } elsif ($thesaurus eq 'rvm') {
-            $subject_heading_thesaurus = 'v';
-        } else { # We stored the value from $7 as the thesaurus if there was one
-            $subject_heading_thesaurus = 'z';
-            push @marclist, 'thesaurus-conventions';
-            push @and_or, 'and';
-            push @excluding, '';
-            push @operator, 'is';
-            push @value, $self->{'thesaurus'};
-        }
         push @marclist, 'thesaurus';
         push @and_or, 'and';
         push @excluding, '';
         push @operator, 'is';
-        push @value, $subject_heading_thesaurus;
+        push @value, $thesaurus;
     }
 
     require Koha::SearchEngine::QueryBuilder;
diff --git a/Koha/SearchEngine/Elasticsearch.pm b/Koha/SearchEngine/Elasticsearch.pm
index 1fe6fb1c6f..9463aed1d3 100644
--- a/Koha/SearchEngine/Elasticsearch.pm
+++ b/Koha/SearchEngine/Elasticsearch.pm
@@ -233,7 +233,10 @@ sub get_elasticsearch_mappings {
                 }
             }
         );
-        $mappings->{properties}{ 'match-heading' } = _get_elasticsearch_field_config('search', 'text') if $self->index eq 'authorities';
+        if( $self->index eq 'authorities' ){
+            $mappings->{properties}{ 'match-heading' } = _get_elasticsearch_field_config('search', 'text');
+            $mappings->{properties}{ 'subject-heading-thesaurus' } = _get_elasticsearch_field_config('search', 'text');
+        }
         $all_mappings{$self->index} = $mappings;
     }
     $self->sort_fields(\%{$sort_fields{$self->index}});
@@ -1166,6 +1169,11 @@ sub _get_marc_mapping_rules {
         }
     }
 
+    if( $self->index eq 'authorities' ){
+        push @{$rules->{control_fields}->{'008'}}, ['subject-heading-thesaurus', { 'substr' => [ 11, 1 ] } ];
+        push @{$rules->{data_fields}->{'040'}->{subfields}->{f}}, ['subject-heading-thesaurus', { } ];
+    }
+
     return $rules;
 }
 
diff --git a/Koha/SearchEngine/Elasticsearch/QueryBuilder.pm b/Koha/SearchEngine/Elasticsearch/QueryBuilder.pm
index 53042b4303..d5dbdee886 100644
--- a/Koha/SearchEngine/Elasticsearch/QueryBuilder.pm
+++ b/Koha/SearchEngine/Elasticsearch/QueryBuilder.pm
@@ -564,6 +564,16 @@ our $koha_to_index_name = {
     all             => ''
 };
 
+our $thesaurus_to_value = {
+   lcsh => 'a',
+   lcac => 'b',
+   mesh => 'c',
+   nal  => 'd',
+   notspecified => 'n',
+   cash => 'k',
+   rvm => 'v',
+};
+
 sub build_authorities_query_compat {
     my ( $self, $marclist, $and_or, $excluding, $operator, $value,
         $authtypecode, $orderby )
@@ -588,6 +598,8 @@ sub build_authorities_query_compat {
     }
     for ( my $i = 0 ; $i < @$value ; $i++ ) {
         next unless $value->[$i]; #clean empty form values, ES doesn't like undefined searches
+        $value->[$i] = $thesaurus_to_value->{ $value->[$i] }
+            if( defined $thesaurus_to_value->{ $value->[$i] } && $indexes[$i] eq 'subject-heading-thesaurus' );
         push @searches,
           {
             where    => $indexes[$i],
diff --git a/admin/searchengine/elasticsearch/mappings.yaml b/admin/searchengine/elasticsearch/mappings.yaml
index e892f9126c..2644bea859 100644
--- a/admin/searchengine/elasticsearch/mappings.yaml
+++ b/admin/searchengine/elasticsearch/mappings.yaml
@@ -805,24 +805,6 @@ authorities:
         sort: ~
         suggestible: ''
     type: ''
-  Subject-heading-thesaurus:
-    label: Subject-heading-thesaurus
-    mappings:
-      - facet: ''
-        marc_field: 008_/11
-        marc_type: marc21
-        sort: ~
-        suggestible: ''
-    type: ''
-  Subject-heading-thesaurus-conventions:
-    label: Subject-heading-thesaurus-conventions
-    mappings:
-      - facet: ''
-        marc_field: 040f
-        marc_type: marc21
-        sort: ~
-        suggestible: ''
-    type: ''
   authtype:
     label: authtype
     mappings:
diff --git a/t/db_dependent/Heading.t b/t/db_dependent/Heading.t
index 6cbb2ac054..7aa14c94aa 100755
--- a/t/db_dependent/Heading.t
+++ b/t/db_dependent/Heading.t
@@ -104,8 +104,7 @@ subtest "_search tests" => sub {
     $terms = $search_query->{query}->{bool}->{must};
     $expected_terms = [
         { term => { 'match-heading.ci_raw' => 'Uncles generalsubdiv Fiction' } },
-        { term => { 'subject-heading-thesaurus-conventions.ci_raw' => 'special_sauce' } },
-        { term => { 'subject-heading-thesaurus.ci_raw' => 'z' } },
+        { term => { 'subject-heading-thesaurus.ci_raw' => 'special_sauce' } },
     ];
     is_deeply( $terms, $expected_terms, "Search formed as expected with second indicator 7 and subfield 2");