[spiderserie4]

whats the difference between a series 3 and 3.5, I have a 1990 spider velocie and im looking for ac pressure switch ?

series 3.5 (MY1990 in the USA) is basically the motronic injected engine from the S4 (less power steering) in a S3 body.

the trinary (pressure) switch is mounted on the receiver/dryer

numbers #7 & #8 in this page from the parts book: