diff --git a/lib/rails_admin/config/fields/base.rb b/lib/rails_admin/config/fields/base.rb
index e33ca3066a..53a71128e1 100644
--- a/lib/rails_admin/config/fields/base.rb
+++ b/lib/rails_admin/config/fields/base.rb
@@ -88,7 +88,7 @@ def virtual?
                 table_name, column = f.split '.'
                 type = nil
               elsif f.is_a?(Hash)                                              #  <Model|table_name> => <attribute|column>
-                am = AbstractModel.new(f.keys.first.to_s.classify)
+                am = f.keys.first.is_a?(Class) && AbstractModel.new(f.keys.first)
                 table_name = am && am.model.table_name || f.keys.first
                 column = f.values.first
                 property = am && am.properties.find{ |p| p[:name] == f.values.first.to_sym }
diff --git a/lib/rails_admin/config/fields/types/belongs_to_association.rb b/lib/rails_admin/config/fields/types/belongs_to_association.rb
index 6d2e22261c..54301c3f52 100644
--- a/lib/rails_admin/config/fields/types/belongs_to_association.rb
+++ b/lib/rails_admin/config/fields/types/belongs_to_association.rb
@@ -18,7 +18,7 @@ class BelongsToAssociation < RailsAdmin::Config::Fields::Association
           end
 
           register_instance_option :searchable do
-            @searchable ||= associated_model_config.abstract_model.properties.map{ |p| p[:name] }.include?(associated_model_config.object_label_method) ? [associated_model_config.object_label_method, {self.abstract_model.model.name => self.method_name}] : {self.abstract_model.model.name => self.method_name}
+            @searchable ||= associated_model_config.abstract_model.properties.map{ |p| p[:name] }.include?(associated_model_config.object_label_method) ? [associated_model_config.object_label_method, {self.abstract_model.model => self.method_name}] : {self.abstract_model.model => self.method_name}
           end
 
           register_instance_option :partial do
diff --git a/spec/lib/fields_spec.rb b/spec/lib/fields_spec.rb
new file mode 100644
index 0000000000..3c25aba4ac
--- /dev/null
+++ b/spec/lib/fields_spec.rb
@@ -0,0 +1,82 @@
+require 'spec_helper'
+
+describe RailsAdmin::Config::Fields::Base do
+  describe '#searchable_columns' do
+    describe 'for belongs_to fields' do
+      it "should find label method on the opposite side for belongs_to associations by default" do
+        RailsAdmin.config(Team).fields.find{|f| f.name == :division}.searchable_columns.should == [{:column=>"divisions.name", :type=>:string}, {:column=>"teams.division_id", :type=>:integer}]
+      end
+    
+      it "should search on opposite table for belongs_to" do
+        RailsAdmin.config(Team) do
+          field :division do
+            searchable :custom_id
+          end
+        end
+        RailsAdmin.config(Team).fields.find{|f| f.name == :division}.searchable_columns.should == [{:column=>"divisions.custom_id", :type=>:integer}]
+      end
+    
+      it "should search on asked table with model name" do
+        RailsAdmin.config(Team) do
+          field :division do
+            searchable League => :name
+          end
+        end
+        RailsAdmin.config(Team).fields.find{|f| f.name == :division}.searchable_columns.should == [{:column=>"leagues.name", :type=>:string}]
+      end
+    
+      it "should search on asked table with table name" do
+        RailsAdmin.config(Team) do
+          field :division do
+            searchable :leagues => :name
+          end
+        end
+        RailsAdmin.config(Team).fields.find{|f| f.name == :division}.searchable_columns.should == [{:column=>"leagues.name", :type=>:string}]
+      end
+    end
+    
+    describe 'for basic type fields' do
+      
+      it 'should use base table and find correct column type' do
+        RailsAdmin.config(FieldTest).fields.find{|f| f.name == :text_field}.searchable_columns.should == [{:column=>"field_tests.text_field", :type=>:text}]
+        RailsAdmin.config(FieldTest).fields.find{|f| f.name == :integer_field}.searchable_columns.should == [{:column=>"field_tests.integer_field", :type=>:integer}]
+      end
+      
+      it 'should be customizable to another field on the same table' do
+        RailsAdmin.config(FieldTest) do
+          field :time_field do
+            searchable :date_field
+          end
+        end
+        RailsAdmin.config(FieldTest).fields.find{|f| f.name == :time_field}.searchable_columns.should == [{:column=>"field_tests.date_field", :type=>:date}]
+      end
+      
+      it 'should be customizable to another field on another table with :table_name' do
+        RailsAdmin.config(FieldTest) do
+          field :string_field do
+            searchable :nested_field_tests => :title
+          end
+        end
+        RailsAdmin.config(FieldTest).fields.find{|f| f.name == :string_field}.searchable_columns.should == [{:column=>"nested_field_tests.title", :type=>:string}]
+      end
+      
+      it 'should be customizable to another field on another model with ModelClass' do
+        RailsAdmin.config(FieldTest) do
+          field :string_field do
+            searchable NestedFieldTest => :title
+          end
+        end
+        RailsAdmin.config(FieldTest).fields.find{|f| f.name == :string_field}.searchable_columns.should == [{:column=>"nested_field_tests.title", :type=>:string}]
+      end
+    end
+    
+    describe 'for mapped fields' do
+      
+      it 'should find the underlying column on the base table' do
+        RailsAdmin.config(FieldTest).fields.find{|f| f.name == :paperclip_asset}.searchable_columns.should == [{:column=>"field_tests.paperclip_asset_file_name", :type=>:string}]
+        RailsAdmin.config(FieldTest).fields.find{|f| f.name == :dragonfly_asset}.searchable_columns.should == [{:column=>"field_tests.dragonfly_asset_name", :type=>:string}]
+        RailsAdmin.config(FieldTest).fields.find{|f| f.name == :carrierwave_asset}.searchable_columns.should == [{:column=>"field_tests.carrierwave_asset", :type=>:string}]
+      end
+    end
+  end
+end
\ No newline at end of file