AC VACUUM SWITCH 2571501 AND 2096084 QUESTIONS

The vacuum control is separate from the electric control. The electrical part operates the fan motor and A/C compressor clutch, and is just a simple mechanical switch. The vacuum control works all the servo flaps, and in most models, the water valve under the hood. Any vacuum leak (broken nipples or bad slide valve/switch) can result in nothing working vacuum-wise. The internal slide wafers are what move the two switches. They can jamb, break, get gummed up, and cause all sorts of problems. It's also very common for the plastic rivets to break off the back by people pushing too hard on the buttons. I always tried to match the part numbers when interchanging those controls to avoid the problems that you're having. As D67D mentioned, you can test the different wire terminals and maybe find ones that can be used with your application.