How do you disconnect the cruise control on a 1993 Mercury Cougar?

That all really depends on if you want to disconnect it or, remove it. I'm not sure how to remove it, but to disconnect it.... Find the throttle linkage under the hood, this is where you can move your throttle to increase your RPMs without being in the car. There will be 3 cables attache to it, 2 on the top and 1 on the bottom. The two on top should be connected together. The one on the bottom is the cable for your cruise control. Remove that cable and there you go. The cable is held on to the throttle body by a plastic bushing type clip, you can try to pull the cable out of this to remove it, but I would suggest breaking the bushing out in case you decided that you wanted to put it back on, the bushing would cost probably about $10-20 less to replace pending on where you go.

Spyder

We had trouble with the cruise control on a 1991 Cougar. The plastic piece Spyder talks about broke and the cable fell out of the bracket. It may not happen, but the black plastic square piece on the cable looks like it could fall and get lodged between the throttle body, which would cause the accelerator to get stuck. I think we are going to try tying the cruise control cable's black plastic square piece off with a cable tie so it cannot block the throttle body. Might want to ask someone that knows for sure before you do this to be safe.