I recently purchased a 98 ranger 4x4 with the 3.0 and 5 speed manual.

After driving for about 15 minutes the speedometer and odometer quit working. It just drops to 0. There's no bouncing, it's just dead.

The ABS light never comes on. (except, of course, for the first couple seconds when the truck is started)

I replaced the ABS sensor in the differential(an aftermarket job from Oreilly's). I made sure to clean the mating surface well and squirted some contact cleaner on the multi-plug. I still experience the same symptoms.


This afternoon, I pulled the sensor off and took a peak at the tone ring. It looked fine(at least the bit I could see through that hole) so I poked a screwdriver inside and gently pushed on the tone ring to see if it was loose which didn't see m to be the case. I then took some resistance measurements at the big multiplug under the driver seat. These matched what I saw measuring right at the sensor--about 1500 ohms.

Any other ideas on things to check? Should I pull the differential cover off to do a better inspection of the tone ring? Might using the genuine motorcraft sensor possibly help things?

Thanks for any ideas,
arnold

 

Check fuse #25 (7.5A) in the passenger compartment fuse box.

Any problems with the transmission shifting?

 

Fuse 25 looked good. I replaced it anyway just for good measure

No problems with the transmission shifting since it's a manual. I don't have cruise control so no way to narrow it down there.

If I open the differential up, should a problem with the tone ring be pretty obvious?

Whatever the problem is seems to be dependent on something warming up. The longer the truck has sat and the colder it is outside both result in the speedo working longer.

 

It looks like I finally got this figured out. I opened up the rear differential (I needed to change the fluid anyway, right?) and could find nothing suspicious with the ring gear.

I then did some continuity tests green/black & pink/red wire at the big multi-plug under the seat. Nothing seemed wrong.

We had a warm day several weeks back and I was running the a/c, and, strangly enough, the speedo never quit working. Weird. This lead me to think that SOMETHING (wiring, GEM, cluster itself) had to be failing intermittently when it warmed up.

I also found that I can sometimes give the dash a sharp whack with a fist and bring the speedo back to life, at least for a mile or two.

I bought a DMM with a frequency meter (like $30 from harbor freight) and confirmed that the input to the GEM never quit. Likewise, the Gray/black wire continued carrying a frequency signal even when the speedo quit. (I'm sure an oscilloscope would be better for this so you could see the quality of the waveform, but I can't really afford one).

At this point I decided that it seems likely the problem resides somewhere in the cluster itself. I got a different one (actually from a 98 explorer, and the odo reading nearly matched my existing one!) today from the u-pull yard for $25. So far so good. Drove around about an hour and no problems yet.

Anyway, I hope that info helps somebody someday

FWIW, I found this thread very helpful.

 

GOOD JOB! Congrates and thanks for posting your results!

 

Hello, stumbled upon this thread as my truck (same as OPs) is having the exact same problem and I have done very nearly the same steps.

Do you guys know if it's possible to replace the speedometer/odometer gear/motor and what the part number(s) might be?

Similar to what's done here:
I'm not even positive the gears are the culprit but would like to try if possible.

 

I came by the inexpensive but powerful ELM scan tool & running FORScan diagnostic software on my laptop to help me focus my ABS/speed sensor woes. The speed-o uses the rear differential ABS speed sensor PID to do it's thing, so the ELM running FORScan which is tweaked for Fords, is a very good diagnostic tool to help focus a trouble shoot.

It pointed me Right to the rear ABS speed sensor, which on my Ranger is atop the front center of the rear differential & got my trouble shoot back on track, even though the speed sensor had passed a couple of other trouble shooting quick checks.
The rear ABS speed sensor has earned it's place in being the #1 suspect in speed-o, tranny shifting, cruise control & ABS woes, as well as it's wiring & the instrument cluster in about that order.

Seeing as how you seem to like turning your own wrenches, for consideration here is a thread on the ELM & FORScan I started after that successful trouble shoot. It really is a very good tool to have in our electronic tool box for todays computer controlled vehicles.
https://www.ford-trucks.com/forums/1...-scantool.html

Post up All trouble code Number clues it finds.

 

I concur with pawpaw 100%. Just last week, I finally picked up an ELM scanner which - by using the FORscan app - I connect up with my smartphone. What a great tool! The amount of data that it provides - in real time - is amazing. I'm currently using it to help my brother out with the now infamous F-150 Ecoboost misfiring problem that Ford is having with that engine in that vehicle (while also wondering if the new 2.3L Ranger Ecoboost going to have the same issues over time)?

What's also real cool about ELM/FORscan is the way it can access so many Ford PIDs...one example is that, when I scanned my Ranger's GEM, there were a couple of codes that pointed to a problem with a 4WD-related solenoid. Well, I know that my 4WD is working fine, so I was a little bit perplexed by the codes at first, but then I remembered that several years ago I removed the factory vacuum hubs from my truck and installed AVM manual lockers. Doing that meant that the PVH solenoid was taken out of the equation and is no longer used. I plugged the vacuum lines going from the PVH solenoid out to the hubs. So it turns out that, the solenoid is feeling lonely and forgotten, so it's telling the GEM that it has a problem. Hence the codes.

 

Rockledge, Good to hear you finally broke down & decided to give the ELM & FORScan a try & are favorably impressed with what it can offer up on a trouble shoot.
If we invest in it's Modest cost & spend a little time learning how to utilize it on our vehicle repairs, it can quickly help focus a trouble shoot & thus pay for itself, as it did for me on my First use, in scanning my ABS computer & finding & fixing my ABS problem.
The ELM cost was Way less than it was going to cost me to have a garage scan the ABS computer, because my Actron CP9150 scan tool couldn't look at more than the Engine computer, so was of Very limited use on that woe.

 

I have the same Actron unit with the same limitations. ELM/Forscan blows it out of the water in terms of functions and capabilities.

Another example of how ELM/Forscan has already helped me: I had a pending P1000 readiness code stored in my Ranger's PCM for several days because I had erased all prior codes in order to start "fresh" with my new diagnostic toy. After a couple of days, though, I was getting a little antsy because I had a Feb. 3 deadline to get the truck emissions tested (or otherwise fork over a late fee). After re-reading the Ford Drive Cycle protocol, I noticed that the IAT had to be at least 40*F in order for the EVAP Monitor part of the test to be completed. Well, it's been in the 20's and 30's around here temp-wise which means it's been difficult to get the intake air over that 40* threshold. Yesterday afternoon it was in the low 40s so I dropped what I was doing and took another stab and completing the drive cycle. I was able to ensure that the IAT temps were indeed within the testing parameters by monitoring real-time IAT data using ELM/Forscan. I wouldn't have been able to do that with the Actron tool.

Long story short: after performing the steps in the Drive Cycle again, I scanned for codes and voila the readiness code was finally gone. I had the truck emission tested this morning and it passed with flying colors.

 

The only thing that the ELM & FORScan are short on is a power balance test, which the Actron CP9145/9150 Can do & that's really handy when we have a cylinder acting out & don't know which one it is, or what might be causing the problem. SO, hopefully they'll eventually get around to putting up a power balance test on FORScan for we gassers.

If my memory is right I believe my Actron CP9145/9150 scantool will monitor IAT, but I think we have to scroll all the way down the list to the bottom to find it.

 

I was mistaken, my Actron is the CP9135 model, not the 9150.

The 9135 doesn't provide any real time sensor data, nor does it have the ability to do a power balancing test. Aside from reading and erasing codes, the only other useful thing it does is show the status of the OBDII monitors.

So it's easy to see what a big step up ELM/Forscan is for me.

 

Yup the ELM/FORScan combo would be a BIG step up in diagnostics ability over the CP9135, so I can see how your so favorably impressed. It was a Big step up for me, as it could access all of the 99 Ranger computer/controllers, which included the GEM that controls so many functions & I really needed that.

Anyway, those of you having speed-o, cruise control, ABS, tranny shifting woes, have your ELM/FORScan combo scan for trouble code clues, Before replacing the dash, or reworking the gear set, as the problem may be the rear ABS speed sensor, or it's wiring & a trouble code scan could help focus your trouble shoot & save some time, money & frustration.

 

Thanks for the tip on the ELM/FORScan. I'll look at ordering one off Amazon.

One question though: if my cruise control works while my speedometer is showing zero miles an hour, would that indicate that all the electrical signals are working, but the problem lies in the instrument cluster?

 

Well maybe, has/is the speed-o been intermittent, or making a grounding sound, are you having any tranny shifting problems, do you have a lit or intermittently lit ABS light, does the cruise control sometimes drop out, or not want to take a set, do you have a lit CEL?
Best to have the scan tool search for pending, or set trouble code clue numbers & post up All code Numbers found, then let the code clues suggest how to proceed.
Be cautious where you buy off Amazon. Make sure the vendor will back up the ELM if you have problems with it. TCCA members recommend seller BAFX & I am aware of a couple of folks on this forum that have had a positive purchase experience with them. If in doubt, call BAFX with any questions, they seem to be customer oriented.

Let us know what you find.