This SAE Recommended Practice establishes for trucks, buses, and multipurpose vehicles with GVW of 4500 kg (10 000 lb) or greater: a. Minimum performance requirements for the switch for electrically powered or electro-pneumatically windshield wiping system. b. Uniform test procedures that include those tests that can be conducted on uniform test equipment by commercially available laboratory facilities. The test procedures and minimum performance requirements, outlined in this document are based on currently available engineering data. It is the intent that all portions of the document will be periodically reviewed and revised as additional data regarding windshield wiping system performance are developed.