Speedometer vs wheel sensor ????

[Robdaparamedic]

I have a 2000 Windbag and I've become quite intimate with her. I haven't had a speedometer in almost a year. I finally have some cash and thought I would get this fixed. I started with getting a speed sensor. Aamco did a diagnostic and they said it's not the sensor. Not that there was a chance in hell to get at this thing. Second, I replaced a wheel bearing last year and the ABS sensor broke off while I was taking it out and I thought this might be related??? I've had a dealer and 2 mechanics tell me that they (speedometer/ABS) aren't related. Tranny shop says it's someething that relays the information from speed sensor to computer or computer to Odometer....Anyone run into this problem?? No fuses blown, no switch under master brake cylinder. Of course I have no Cruise control, since the speedometer isn't working. Any help would be greatly appreciated.

Rob
I have Garmin that tells speed I'm traveling in case your wondering.

[tomj76]

The velocity speed sensor in the transmission puts out a signal that is used by the PCM, the Cruise Control, and the electronic speedometer. Some Windstars (such as mine) have a mechanical speedometer that runs from an old fashioned speedometer cable. I believe (without consulting the service manual) that the ABS system might also use the speed sensor signal.

Since your cruise control and speedometer are both not working, the first guess would be the VSS, but since you're not getting any codes from the PCM (or erratic drivibility issues), it sounds like the PCM is getting the signal but not the other devices. I'd try to confirm the VSS signal to the instrument panel, but might require an oscilloscope. As an alternative, you could do a resistance/continuity check from the VSS wire at the PCM connector to the VSS wire at the speedometer connector. My guess is that the resistance is very high.

[wiswind]

Do you have the mechanical or electronic speedometer?
The standard speedometer is the mechanical one......a hard cable from the speedometer to the speed sensor that mechanically spins.
The speed sensor, from what I have read, has both a mechanical output (for the mechanical speedometer cable) and a electronic output (for the PCM).

My ScanGauge OBDII code reader give me a readout of the speed as the PCM sees it.
This is what is used by the cruise control.

So, most any shop can connect to the OBDII port.....drive the vehicle and see if there is a speed indication that can be read at the OBDII port.

Not sure if this link will work......part at rockauto http://www.rockauto.com/catalog/x,ca...parttype,10634

The link is for the 2000 3.8L windstar.
I could be all wet on this one....as they list only 1 part for 2000 and for 1996, they list 1 for Electronic dash and a different one for Mechanical dash.........
However, what I said about being able to read the vehicle speed at the OBDII port with a capable reader still stands true.......the PCM needs to know the vehicle speed.

I understand that this part would be an easy replace....except for the location.....which makes it less than easy.

Now for the cruise control......don't forget to check the brake pressure switch on the bottom of the master cylinder......if leaking (damp or wet with brake fluid), it could be the cause of the cruise control issue......and can cause a fire.
Cheap and easy to fix.

For my 1996, the front wheel speed sensor is replaced by replacing the whole half shaft....not individually replacable.
The rear wheel sensor is replacable......bit of work but do-able as a individual part.

[Robdaparamedic]

Thanks for the reply...Speedometer is mechanical but odometer is digital. NO leaks or corrosion at MBC. The speedometer was intermitant and thus the CC was also intermitant. I recently purchased the sensor and then returned it. There is one end that has set screw and plastic round end that plugs into transmission. The other end has a electric plug end. Pretty simple it would appear. It is impossible to get at. Amco transmission did a diagnostic and told me that this sensor was not the problem. I'm sure a second opinion won't hurt. Need someone who has had same problem...PLEASE !!

Rob

[tomj76]

The mechanical speedometer is not needed for proper operation of the cruise control. The speedometer itself generates no electrical signals.

Since cruise control is an electrical device, it's only speed input is the VSS signal. This signal not only goes to the cruise control, but it also is used by the PCM. If the VSS has failed, you'd know it because the transmission would shift erratically, the O/D light would blink, and you'd have codes stored in the PCM. (I know this b/c the connector to my VSS came loose once, which as you mentioned was a lot of trouble to get to).

If you have a mechanical speedomenter and there are no codes or you have not noticed the conditions mentioned, then I wonder if you could have two different problems here.

[Robdaparamedic]

You and me both. I'm just not ready to spend $200 - 400 to find out. I'm replacing the caliper today and some brake pads and then going to enjoy the weekend. Thanks.

Rob

[tomj76]

If the speedometer reads zero all the time, and the odometer isn't recording mileage, then maybe it's only the speedometer cable. After the VSS there are two places where the cable has couplings. One is in the back of the instrument cluster (which is acessed from under the dash), the other is in the engine compartment, toward the driver side. They are both somewhat of a pain to get to, but much less than the VSS. I'd go with the instrument cluster first, and check that the cable is turning with the front wheels.

If the odometer is still recording miles, then the speedometer itself is likely to be the problem. I had mine repaired once, at about half the price of a Ford replacement.

[Airjer_]

Originally Posted by wiswind

For my 1996, the front wheel speed sensor is replaced by replacing the whole half shaft....not individually replacable.
The rear wheel sensor is replacable......bit of work but do-able as a individual part.

Do you have the speed sensor and exciter ring mixed up? Isn't the exciter ring on the axle shaft and the speed sensor mounted to the hub?

[wiswind]

You are correct......the wheel sensor is replaceable......exciter ring......more work.