Success! My 98 Boxster with mechanical throttle now has a working Porsche cruise control. It was a big job, but I think it will be worth it.
I got a used 4 stalk and cruise control module (with partial wiring) and used the directions I found on Renntech.
The hardest part was wiring the bridge points, followed closely by installing the cruise control module to half of my gas pedal assembly.
Now that I have a 4 stalk control, I added the OBC wires so that works too.
I also added rear speakers, changed the front speakers, changed to a CDR-220 and added and iPod cable. It’s like a new car now!
I went for a test drive and all the functions work. It seems to hold speed very well. I check the brake and clutch disconnects too.
The only thing I noticed on the test drive is left turn signal needs a little extra pressure to work reliably. It is a "new to me" switch as it was on the used 4-stalk. Of course the switch on my 2-stalk worked fine. I don't think they are interchangable. Always something
But I have cruise control