It's below the gear selector lock button on the automatic transmission cosole shift
Push the button on your transmission gear selector lever that is below the thumb switch that you push to select a gear
There is no separate switch for the overdrive, simply put the gear selector in the overdrive position. It looks like a D inside a square. Not all Chevy Celebrities have the overdrive feature, it was an extra cost option.
In the ( 1997 ) Mercury Mystique : The fuel pump shut off switch ( inertia switch ) is in the drivers footwell behind the kick panel ( there is an access hole ) * it's near the inside hood release *
Overdrive is the normally allowed position It won't shift into overdrive until the speed is higher anyway ( such as on the highway / freeway ) If you are towing something , or are driving in hilly country where the transmission is constantly shifting between overdrive and drive , you want to switch the overdrive off using the switch on the end of your gear selector lever ( P R N etcetera , the O/D OFF light will appear in your dash )
That would be the OVERDRIVE selector switch.
In the drivers footwell behind the kick panel ( there is an access hole in the panel ) according to the 1999 Mercury Mystique Owner Guide
In a ( 1996 ) Mercury Mystique the fuel pump shut off switch ( inertia switch ) is in the drivers footwell behind the kick panel by your left foot . There is an access hole through the panel
If it is the same as the ( 1996 ) model year of Mercury Mystique , the fuel pump shut off switch ( inertia switch ) is in the drivers footwell , behind the kick panel ( there is an access hole ) * near the inside hood release
on the back of the block behind the intake
It might be the transmission range selector
The fog light switch on the 98 Mystique is on the headlight switch. When you turn on the headlights, pull the switch towards and the fog lights should come on. Here is a link to the owners manual for the 98 Mystique http://www.analogstereo.com/pdf/om/mystique_owners_manual_1998.pdf
Even after pushing the overdrive cancel button again ? to allow the overdrive feature On my Ford Explorer with the column shift automatic , the overdrive switch is on the end of the gear selector lever