Speedometer not working
 

Need help diagnosing a speedometer issue.
sold a 2000 Ranger to my sons friend. It was working at the time . A couple weeks ago he calls up and says speedometer is not working . Googled issue. 1st response was to replace vehicle speed sensor on rear axle. He did . Still not working. Took truck to a friends house ( he’s a mechanic) asked him to put his diagnostic computer on it. It came back saying no power to vehicle speed sensor , and TCC was not working.
I’m looking over it today , the first thing I notice . And it use to annoy the heck out of me is . The door chime isn’t working. So I start looking to make sure all the fuses are correct , not blown , and not missing.
I looked up how to disable a door chime . I see there is a big bundle of wires behind the center console. Idk if he took it open himself to disable , and cut a wire to disable it. Maybe cut the wrong wire . Idk.
figure I would ask before I dig into taking the dash apart.
I looked at the wires from the vehicle speed sensor. I don’t see any breaks in visible wires . Haven’t pulled wires out of the loom yet to check
any ideas ?
my time is limited , and him and his mom are wanting me to buy back the Ranger if I can’t fix this

Welcome to the forum

1998-2000 Rangers have a different setup for speed signal than other years, just FYI

These years do use the rear axle ABS sensor signal for speedo, but also for the ABS, so if ABS light is working(key on) but doesn't come on when driving the rear axle sensor is OK, as you/he found out

Ford spliced into these 2 ABS sensor wires(not sure where) and ran them to the GEM module behind the radio, so ABS module and GEM module share the rear axle speed signal
This speed signal is 20,000ppm(pulses per mile)
Ford speedometer, computer and cruise module need 8,000ppm speed signal

So the GEM module Converts the 20,000ppm to 8,000ppm and sends it out to Speedometer, Computer and cruise module

You had the codes read, if computer was not seeing an 8,000ppm signal then it would set a code, P0500, and you didn't see that?
So if no P0500 code but no speedometer then problem is the speedometer not the speed signal

If you have cruise you can check if it works as well, if so, that would further confirm GEM is working and problem is in the instrument cluster/speedometer

Least expensive and easiest would be to swap the cluster, 1996 to 2003 are plug and play no wiring changes, with or without Tachometer

With cluster out, it has 16 pin, 12 pin and 10 pin connectors, the 12 pin connector, pin 1 is a grey/black wire, that's the speed signal from GEM/pin1 also grey/black wire
You can test continuity, between these 2 wire
If they are connected then replace cluster
If they are not connected add another wire, splice in to GEM/pin1 wire do not cut it, and cut the 12 pin/pin 1 grey/black wire and butt connect the added wire



So just a follow up for 1998-2000 Ranger/B-series speed signals
No speedo and ABS light on, bad rear axle sensor
No ABS light then sensor is OK

No speedo and Code P0500 from computer, then GEM module may be at fault, or wiring to or from GEM
No speedo and no P0500, then speedo is at fault or wiring to speedo from GEM

https://cimg7.ibsrv.net/gimg/www.ran...f3d300c91.jpeg
Yes I did have a 0500 code. Sorry for reflection in picture. It was bright outside. If you are able to zoom in . You can see code 0500 And a code for the TCC . Next issue I have to take care of. I do have another instrument cluster from a 97 I can swap out if needed

Thanks for the info Ron. It will put me in the direction I need to go .
I hope this fixes the TCC issue to. I’ll let you know this weekend how it turns out
thanks again

If you also have P0500 with no speedometer then GEM module is not outputting a speed signal
And yes, that would be the TCC issue

Best to test wiring from rear axle sensor to GEM first
Get a long jumper wire and OHM or Continuity meter
Pull out the radio to access GEM wiring
Unplug rear axle sensor
Connect jumper wire to red/pink wire at sensor
Then test pin 9 red/pink wire at GEM for connection

Do the same with green/black wire on pin 18 of GEM

If either shows no connection then you will need to splice in and run a new wire from rear axle sensor to GEM

If connections are OK then its most likely a GEM module issue
Pin 1 on the GEM is the grey/black SPEED OUT wire that runs to speedo, computer and cruise
You can check it for corrosion or ???
If you want to pull the cluster you can check continuity to grey/black wire on 12pin pin1

GEM wiring below, 18pin connector has the speed IN and speed OUT wiring

Found a GEM module and replaced it . Everything is working again. Still getting a O/D light flashing , but when you turn truck off and back on it goes out. Truck shifts good . And scoots down the road.
thank you for your help.

Check codes and see if it has the P0500, no speed signal at computer

You need an OBD2 reader that can "see" Transmission codes, P0700 to P0803 most can't "see" those codes
Flashing OD light means a transmission code has been set, assuming no P0500 code