Installation Instructions: 1. Find the location for the headlight relay under the hood between the headlights. The wiper door vacuum relay location is under the rear right-hand fender well or the left side of the firewall. 2. Mark the placement of the hoses so they can be re-connected later. The original hoses had striping to match the color coded dots on the original relay. The replacement valve is initialed and color-coded for ease of hose re-installation. 3. Unbolt the old relay and replace it with the new one. Re-connect the hoses in their proper positions. An extra filter has been provided as a spare. These filters can also be cleaned by using soap and water only. Size: N/A,Original GM #: 5638427 Car years: 1968, 1969, 1970, 1971, 1972, 1973, 1974, 1975, 1976, 1977, 1978, 1979, 1980, 1981, 1982