glc,
Here the page at Rock Auto that describes the Vehicle Speed Sensor replacement parts - mine would an 'under 8500 GVW' selection. They also list the ABS sensor on this page:

http://www.rockauto.com/catalog/x,ca...parttype,10634

Can't tell what type it is... if new from the dealership is reasonable I may go there to get them.

 

Another option would be to call Tasca Parts or one of the other Ford parts wholesale dealers - and give them your VIN.

 

Don't know what PATS is understand what you mean. The various VSS part descriptions cover 97-03 with both over and under 8500 GVW ratings. I'm gonna confer with Ford to determine if what you say is true. I'm wondering too... gotta wait for the snotty weather to break before I can get under the beast and take out the old part.

 

PATS is the antitheft system with the chipped key, it also has the electronic odometer. The 99+ does not have a gear-driven VSS.

 

So, -is this a 2wd or 4wd?

 

There really isn't enough info from the OP to make it an easy answer lol. I mean, what trans ? transfer case ? Oh well, - I'll point out a few things that may help.

It's not the OSS, so scratch that. The OSS and VSS have the same duties and use the same hole, put it that way lol. The VSS is model/model year dependent. Only the VSS was used for your model year "truck" AFAIK.

IF the Speedometer and Odometer are both inoperative, -then most likely it's the VSS. But you said just the Speedo didn't work, -EVERYTHING else does, so it's NOT the VSS according to your explanation.

IF the Speedometer is inoperative but the Odometer functions properly (it must according to your post) then it's absolutely the instrument cluster. That's your problem I guess, -a little rare.

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ABS - I don't think you have an ABS problem, sounds like bad brake lines IMO -the rubbers. It could be a proportion valve issue, hard to say, you didn't post an ABS light, so I don't think so. You can just replace the module, if you feel like throwing one at it, -if they're cheap enough. Being a 97, going thru the brake system is a real good idea.

 

Thanks for chiming in, jbrew. I'll reiterate a few details:

The speeddo and odo are not working.
I'm in a 2WD truck.

I understand the tranny sensor went digital in, what, 1999? But the parts houses call for the same part in all years up to 2003 - do I need to get the speed sensor from the dealer to be sure? Also, some parts are for an under 8500 lbs. GVW and some are for over 8500 lbs. GVW. This is getting silly complicated... do you think the CC will get itself working too with this sensor replaced?

I've got to do a real brake inspection on this vehicle - don't know the condition of shoes/pads or anything. I'm going to replace the ABS sensor just to avoid a later repair.

 

The over 8500 GVW is for a Super Duty.

 

The 97/98 V6 Essex equipped trucks were digital. The V8 Modulars were analog those years. As far the cluster odometers. So if you see digital offerings when hunting parts, that's why. Those models and later MY's use the output shaft speed (OSS) sensor with a magnetic pickup (digital).

The VSS you can get anywhere that carries them AFAIK. I haven't heard of knock-offs or bad ones.

It's not really complicated once you know what they did lol. It can be difficult finding that info, since it's generally obtained thru a lot of hands on situations with the different models. You eventually figure it out.

Vehicle Speed Sensor (VSS) 9E731

The speedometer with an odometer and a trip odometer receive information from the vehicle speed sensors (VSS),-as well as a tachometer, if equipped.
The Cruise Control WILL NOT function without the speedometer being operational.

Description

The vehicle speed sensor (VSS) (model-dependent) is a variable reluctance sensor that sends an AC/frequency signal to the powertrain control module. The vehicle speed sensor signal is used by the powertrain control module to calculate vehicle speed in mph and determine shift scheduling and electronic pressure control.

Symptoms

Harsh engagements, firm shift feel, abnormal shift schedule; unexpected downshifts can occur at closed throttle, abnormal torque converter clutch operation or torque converter clutch engages only at wide-open throttle. May flash transmission control indicator lamp.



From Service,-

Remove the vehicle speed sensor (VSS)

1.Disconnect the harness connector.
2.Remove the bolt.
3.Remove the VSS.

Install the vehicle speed sensor (VSS)

1.Install the VSS.
2.Install the bolt.
3.Connect the VSS electrical connector.

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The ABS system

This system usually will ALWAYS forward a cluster light when there's a problem.

The anti-lock electronic control module performs system tests during start-up and normal operation. The RABS valve, rear brake anti-lock sensor, and fluid level circuits are monitored for proper operation. If a concern is found, the anti-lock electronic control module deactivates and the yellow ABS warning indicator illuminates.

The ABS is a pretty good design in these trucks and usually last the life of the vehicle. It's possible to have problems of course, but you'll usually get a CEL.

The RABS Diagnostic Test Connector is under the dash for troubleshooting. The Anti-Lock Electronic Control Module is under the dash as well, and is replaceable (97 Part # - 2C018). So is the Rear Brake Anti-Lock Sensor on the rear axle (97 Part # - 2B190).

The proportion valve below the master cylinder is the RABS valve. The #1 problem with the brake systems on these trucks is the rubber brake lines. They break down on the inside and restrict flow needed for the twin piston calipers. When heavy braking is required, this restriction causes the rubber brake lines to blow up like a balloon vs applying pressure to the calipers. Most problems with these systems reverts back to faulty rubber brake lines.

From - Ford Service for the 97/98 F150's. The ABS in further detail, -

The rear anti-lock brake system (RABS) continuously monitors rear wheel speed with a rear brake anti-lock sensor mounted in the rear differential case. When the teeth on the rear brake anti-lock sensor ring, mounted on the ring gear, pass the RABS sensor pole piece, an AC voltage is induced in the sensor circuit with a frequency proportional to the average rear wheel speed. In the event of an impending lockup during braking, at vehicle speeds above approximately 8 kph (5 mph), the anti-lock electronic control module senses the drop in rear wheel speed. If the rate of deceleration is excessive, the anti-lock electronic control module activates the RABS valve, causing the isolation valve to close. With the isolation valve closed, the rear wheel cylinders (2261) are isolated from the brake master cylinder and the rear brake fluid pressure cannot increase. If the rate of deceleration is still excessive, the anti-lock electronic control module will energize the dump solenoid with a series of rapid pulses to bleed the rear wheel cylinder fluid into an accumulator built into the RABS valve. This reduces the rear wheel cylinder brake fluid pressure and allows the wheels (1007) to spin at vehicle speed. The anti-lock electronic control module pulses the dump and isolation solenoids in a manner that will keep the wheels rotating while still maintaining high levels of deceleration during braking.

Once stopped, the operator releases the brake pedal (2455), the isolation valve de-energizes and any fluid in the accumulator returns to the brake master cylinder. Normal brake operation resumes.

 

Went down to O'Reilly's and have what should be the correct VSS coming in today. Just $28 for a lifetime Borg-Warner part - beats all the online offerings in price and warranty.

Since the ABS light goes off like it should I'm gonna leave that alone...

 

Well, put a new VSS from O'Reilly's which we checked carefully to go in this vehicle in and the speedo still doesn't work - any ideas? Cluster? Wrong part? Don't know how to check or test further on this...

 

Not sure. All I have is, it's either the cluster or vss.

 

Does the VSS have a gear on it?

 

Just to get back on this effort, I have replaced the VSS - it was gear driven - and it didn't fix anything. Returned the new part and put the old one back in. Am wondering if it is just the speedo assembly even if all the other gauges and tach are working fine. Any way to test the speedo? I'm going to replace the lighting in the cluster anyway...

 

The Speedo and odometer use the VSS on the transmission to send a pulsed signal to the cluster. An an electric motor with gears turn the odometer and move the speedo needle. As stupid as this may sound; pound on the dash above the instrument cluster and see if that fixed the problem. If it does get a replacement gear set and fix the cluster. http://www.ebay.com/sch/i.html?_odkw...+gear&_sacat=0