Where is the Vehicle Speed Sensor - VSS - and how do you replace it on a Ford Windstar?
There is a way to do this from inside the engine
compartment on 1999+ 3.8l Windstars. Tedious & possibly
gonna scratch your arm up, but easier than pulling motor mounts and
Location: Directly underneath the middle spark plug on
the back of the engine - about 3" down, and inserted into the top
of the transmission. There is a metal shield that is held in place
with the same hold-down bolt that secures the sensor.
- Clear the right side of the engine compartment - the rubber
piece & left side of the air cleaner housing. Couple of 5/16
hose clamps, couple of sensor plugs & 1 vacuum line to the back
of the rubber connector.
- Throttle cables & mount - release the 2 cables & 2 10mm
bolts for the mount.
- I would strongly suggest pulling the cowling! As every Windstar
owner knows, this cowling is the biggest impediment to getting
access to almost everything at the backside of the engine. Removing
it isn't a big deal (especially after you've done a few times ;)),
and is detailed in various postings here on Answers.com
- Optional: release the coilpack from its 3 mounting bolts (weird
size, something like 7mm)
NOTE: don't rush and forget to secure the radio noise capacitor
thingy under the leftside hold down bolt.
Getting at the bolt:
- Socket extension combination to clear the angles - 8mm socket +
universal + 6-8" extension + 8-10" WOBBLE extension.
TIP: tape the joints together so your extension
assembly doesn't come apart as you're pushing & pulling it up
- The opening you're aiming for is to go down alongside the
middle sparkplug. There's plenty of interference what with
wires & exhaust manifolds, but this is the opening that aligns
with the top of the bolt.
- Your arm, if it's long enough (thank goodness I have
monkey-arms!), can go down to the right of the braided
covered heater hose and turn left to the backside of the engine.
Once your hand is down there and has figured out where things
are, you're ready to use it to guide the socket into place &
onto the bolt
- Use your left hand to find the correct opening and lower the
This is a totally blind operation! You will never see
the pieces you're working with.
- Have a 2nd pair of hands to help! They come in really handy
when it comes time to operate the wrench.
- NOTE: because of the angles, the top of the socket extension
assembly is going to end up real close to the firewall - thus the
universal + the wobble to accommodate the angles from above.
Assuming you don't dislocate your shoulder or bleed-out from
scratching your arm to shreds, you should be able to get the 25mm
long bolt out!
Lift and remove the cover, and the sensor should rotate in the
open pretty easily.
Removing the sensor: This is the hard part because you
can't easily get upward pull as you twist the sensor in its
opening! Just keep twisting and lifting - it'll come out...
This is one of the most painful, awkward & frustrating
things I have done on a vehicle!
But in my circumstance, well worth the effort.
Btw, don't do this unless you know for 100% sure your sensor has
failed - you're not going to enjoy the experience.
Best of luck! :)
Forget what the manual says! It will have you remove the exhaust
pipe which is hell if its old and rust; and after that you will
have to feel your way around the sensor as the angle is bad. Also,
it puts you hand in a cramped position to try and ratchet the
mounting bolt on the sensor which is on top and away from you.
I had to change mine and this most direct approach that is least
problematic. The sensor is located on top of the transmission right
behind the passenger side rear engine mount. Jack up the car and
support it safely on a jack stand. Then remove the passenger side
front wheel and fender guard to get access to the engine and mount.
You got to remove the mount and mount supporting bracket on the
engine to get enough clearance to the sensor (which requires
lifting the engine some. Last resort you can use your floor jack
and a block of 2x4 wood to do it only don't lift on the oil pan or
crank shaft pulley. I tend to use the area where the oil pan bolts
to the block. Make sure to unbolt the bottom of both the front and
rear engine mount first and then lift slowly and carefully so not
to cause damage anywhere). As soon as I remove the mount, I usually
lower the engine back down to be safe as floor jacks can be
This part is difficult to describe as I can't accurately
remember, but, the transmission has a hump or cap on top of it.
You'll see the sensor plugged into it from the opposite side that
faces away from you. You'll spot the sensor after removing the
mount and you'll see what I am trying to describe. Its common
sense. There is only one bolt and you have to feel around the
sensor for it where it plugs into the hump/cap. I don't remember
the size of the socket but you can research that. Because of the
confine space, use a small socket wrench.
Make sure you clean and wipe the area before removing the
sensor. Otherwise, debris can fall inside the hole where the sensor
goes and re-installing the sensor can be sticky. So a mild lube on
the sensor housing (not the gear!) helps to slide it into the
If your car is really old, it might be wise to purchase an extra
pigtail connector that plugs the car computer into the sensor.
Because the sensor is so close to bank 1 of the engine, the heat
and weather overtime can make the pigtail brittle and it can break
during unhooking. That happened to me.