Keeping your 1968-1982 Headlamps and Wiper Door in working condition is a must. This Vacuum Relay is a main reason of failures or improper operation of your Headlight Bucket or 1968-1972 Wiper Door systems. Replace your faulty units with our high quality reproduction Headlamp Wiper Door Vacuum Actuator Relay. This item is no longer offered by GM and is only offered as a reproduction. As of this listing we know of two manufacturers for these valves. One is very cheaply made and the other that we carry meets or exceeds factory specifications and has been in production for over 20 years. A simple way to tell them apart is the metal air tube connection will be beveled on the higher end valve but on the lower end valve it will be just a straight unfinished cut. The Headlight Actuator Relay installs in between the headlight assemblies and controls the vacuum circuits to extend or retract the headlight actuator to open or close the headlights. This Vacuum Relay Valve serves the same purpose to control the operation of the 1968-1972 Windshield Wiper Door. Please see our other listings for our special price dual kit. This listing is for one C3 Headlight Relay for use on either the left or right headlight or for the windshield wiper door. 1968-1969 used just one relay for the headlights in center of nose near the hood along with one for the wipers located on right fender. 1970-1972 used 2 relays for headlights and one on firewall or fender well for the wiper door. 1973-1982 used a total of 2 relays for the headlights as the windshield wiper door was no longer an option.