cruise switch

I see that the On/Off switch (on steering wheel) is a different part for 2000-03 vs 2004-05. What's the difference?

Since I got this car a few months ago, the cruise control will not stay on unless I keep pressing down on the steering wheel switch. When I do that, it works as it should. I already replaced the steering wheel switch with one from a salvage yard but it works the same as before. I have read that...