Are you sure it's still fully functional? Taken any measurements lately? resistance across those contacts when cold? Full battery voltage at the heater when controller is activated? Had it open to have look inside? I've personally replaced hundreds of those controllers (including the later button type) wrenching on these cars back in the day at dealers. So common for them to have stop functioning in short order, they were considered a tune-up part, automatically issued out over the back counter along with the spark plugs, PCV valves, and filters on almost every car. Why do think there are so many NOS controllers for sale today? Factory tune was so lean, most cars had better cold drivability without the choke spring heater functioning. Most cases, mileage suffered somewhat with the prolonged choke function which tended to help bring the vehicles in for the tune-up in the first place. I have two NOS controllers right now, one lasted about 6-months before I designed something that could handle the heating element current and didn't depend on a small bi-metal strip for its timing.