There are two. a pre-cat sensor and one further down on the exhaust.
TWO.
It has 2 of them.
Four
Hi, I have a 96 ford contour.. they all seem to have emission issues dont they? On mine, I just replaced the 2 it has. They are called upstream and downstream o2 sensors. I liked the prices from rockauto.com where they were shipped from.
The oxygen sensors that connect to the exhaust system. There should be two, and they should screw into the side of the exhaust.
The 1996 Aerostar did not come with a 3.8 V6. It is a 3.0 or 4.0 http://autorepair.about.com/library/firing_orders/bl-ford-firing-96.htm
4 ======================================================= The above answer is correct if you have the 5.0 liter V8 engine in your 1996 Ford Explorer , but if you have the 4.0 liter EFI , V6 engine ( VIN " X " ) there are ( 3 oxygen sensors )
There are four (4)oxygen sensors on the 96 Taurus the two in the back are screwed into the tailpipe on both sides of the Catalytic converter. They are on the top of the pipe so hard to see, but you'll see the wires coming off them. The other two are at the front of the engine.
Not exactly sure how many the '96 has. All the oxygen sensors are located on the exaust. Some years have them just between the engine and the catalytic converter. Other years have them there in addition to another one behind the catalytic converter. They are screwed into the exhaust connected with connectors. Just unplug connector and unscrew them. Then replace. Some of them are really cranked on there though. Just remember DO NOT touch the tip or get anything on the tip of the new O2 sensors.
A person will typically need to check the fuse and rails on the sliding door of a 96 Ford Aerostar fan to see why the door drops after opening. If the door is out of its tracks or the bolts have become lose, it will often drop when operated.
It has oxygen sensors before and after the catalytic converter.