Here is 1 new HVAC A/C & heater blower motor fan relay to fit many Cadillac vehicles 1976-1978 
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: Cadillac; Calais 1976, Coupe DeVille 1976-1978, Eldorado 1976-1978, Deville 1976-1978, Series 75 Limo 1976-1978, Sixty Special 1976