1996 Ford Aerostar Owner's Manual - Page 98
1996 Ford Aerostar Manual
Page 98 highlights
RWARNING Do not use the speed control in heavy traffic or on roads that are winding, slippery, or unpaved. In mountainous areas, at higher elevations, or when pulling a trailer, the speed control may not be able to maintain the preset speed with the transmission in j (Overdrive). To maintain a preset speed with an automatic transmission under these conditions, select Drive by cancelling Overdrive. You can switch to Drive at any speed. For the best fuel economy during normal driving conditions, leave the transmission in j (Overdrive). RWARNING Do not shift the transmission into N (Neutral) with the speed control on. You can use the accelerator pedal to speed up momentarily. When you take your foot off the accelerator, the vehicle will return to the set speed. 117