Here is 1 new HVAC A/C & heater blower motor fan relay to fit many Buick vehicles 1973-1978
Relay has 5 contacts and a mounting tab. 
Relay has many uses; such as: convertible top, fast idle control solenoid, A/C compressor cut out, cornering lights, blower motor, power antenna, throttle control and windshield wiper washer. 
Fits: Buick; Centurion 1973, Electra 1973-1978, Estate Wagon 1973-1978, LeSabre 1978, Riviera 1973-1978