Mack CH/CV/CHD 1MR581A Signal Switch PAI 804134CROSS REFERENCE: 1MR581 1MR581A 20775846 25111277 APPLICATION: Mack CH CHD CV Multiple Use Application. DETAILS: 5 Pin Plug BRAND: PAI 804134 Mack 1MR581A Signal Switch PAI 804134 intended for heavy duty truck parts and truck components. Ensures consistent signal activation and safe driving. All components are proudly manufactured in the U. S. A. by PAI Industries Inc., an ISO9001 certified company with over 50 years of experience in the heavy duty