· Trained (ex)Professional, , 1953-2018 RIP
From your description, it does indeed sound like the seatbelt interlock device. Seatbelt interlocks were mandated by Federal regulations for all vehicles sold in the US for the 1974 model year. In early 1975 however, this mandate was recended and the interlocks were allowed to be bypassed. According to an Alfa issued technical service bulletin, connecting wire number 10 to wire number 13 will bypass the device. If your device is broken, it's replacement is not necessary. Just connect wires 10 and 13 together.