Speedometer does not work?

I see you posted the vehicle as only having 36,000 mile on it. Is it slightly over 36,000? Most people don't know this (hush, hush) but if the vehicle falls within a certain time period after the 3 yr/36,000 warranty, your local dealer may do something called an "after warranty adjustment." This problem could possibly be a sensor. It would be the one mounted to the top of the rear differential. But my suggestion would be: if you can have it done with little or no cost to you, it's worth the phone call. If it is not the sensor, it may well be either the main computer or the instrument cluster. Play dumb when you call and ask if there is any way they can help since it is just outside of the warranty. See what they say, you may be suprised!

I have a 2000 F350 Diesel that had a good speedometer when I bought it. Shortly after, it stopped working. With the speedo wne the odometer and the cruise. The OD light is flashing. When I had it plugged in I got the code for vehicle speed sensor, but I had those replaced and nothing still. I took it back in and they said the problem is the signal from the speed sensors is getting lost somewhere between the abs module and the PCM. They checked the abs system and it had no codes or problems. So does that mean my PCM is bad? Also, the speedo comes on from time to time, then goes out again. Also, if it is the PCM, where is that located so I can take it out and have it tested? Thanks.

Okay, I disconnected the wires from the front of the master cylinder reservoir. When I drove it everything was the same, no speedo, etc. Only difference was the brake light on the dash was illuminated.

Okay, I measured the terminals with the wires disconnected from the reservoir. I am not sure if I am doing it right, but I was measuring on D/C, and A/C in volts and the reading I got was 3.5 to 3.6 volts in D/C and in A/C it was around 4.2 volts. Is that the number you wanted? Also, the vehicle is 2wd, and I believe it is only rear ABS. It is the basic XL model with no options, so I would not think it has 4 wheel anti lock. Is there any way to know for sure?

Hello, I found out how to test resistance which is what you asked for. The reading I got was 6.00, however the setting was set to 20K ohms. So I am assuming that means the reading I got was 6000 ohms? I am not sure how these work, but that is what I think. What would you like me to do next?

Hello, Sorry I was not sure what you wanted before. I just measured with the Ohms set at 2000 across the speed sensor terminals, with the sensor out of the truck and the reading was 1.997. I will stay close to the computer now. I was not expecting such a quick response. Thank you.

Okay, I tested the sensor at 200 ohms and it just gave me a reading of 1, meaning the reading was higher than the setting. At 2000 ohms setting I got readings of 1.997. Yes I inspected the wires and the terminal and found that they looked good. The wires were red, and green with a black stripe. What would you like me to do next?

I tested the two wires that lead back to the sensor at the fender. It gave me no reading at all. I was still on 2000 ohms and there was no reading. Does that mean I have faulty wires somewhere between the sensor and that connection?

Is there any way to test the wires in different spots to try and pinpoint where I am losing the signal?

Thank you very much for your help!! This problem has given even the best shops in my city a tough time. Thanks again.

Not yet. I think I am going to work on it tomorrow. I'll let you know when I find it.

Hello again,
I made a mistake yesterday. I had the meter at the wrong setting. I tried again today at the correct setting and I tested the harness at the fender, it gave me the same reading that I got from the sensor. So the wiring is giving a good signal up to that point. Sorry about that. I need to continue testing. What is the next step?

I removed the driver side battery and pan that it sits in. Is the ABS module silver and has the brake lines going into it? I can not see any wires going into it. What wires am I going to be testing? Can you explain?

never mind, I was able to access the wires from underneath the fender well. I will test the same two wires now.

I found the wires. I had to access them from underneath, not from the top. I tested them at the plug. Same reading as before. Now the next step requires 2 people right? Lift the rear wheels off the ground, make a nick in the black/grey wire at the ABS module, then turn meter to low ac volts, and have someone turn the rear wheels as fast as they can, right? Making sure the black lead goes to ground and the red to the black, grey wire. With the ABS module plugged back in.

Does it matter which rear wheel is spun? and which direction? Also, the ground lead from the meter means just touching it to metal, right? Just want to make sure I do it right.

I had someone spinning the rear wheels while I tested the wires. I had the meter set at 200mV. The initial readings I was getting were around 10.0. As the wheels were turned the readings went up to around 25.0. What is the next step?

Hello, I'm sorry I don't really understand the last instructions totally. The instrument cluster meaning all of the guages from the dash? Then I don't really understand where to put the two lead ends? One at the wheelwell, and the other where? I can't quite picture what you want for me to do.

Okay, I got the instrument cluster out and I found the black/grey wire. It is firmly connected. Now, could you walk me through how to test the integrity of the wire again, please?

Okay, I got it. I did that and I got the same reading, showing consistency through the wire. So, you said that means I have a bad cluster?

Just curious, why does the cruise go out also, when the speedometer and odometer do? Is it connected to them somehow?

Transmission problem
1999 Ford F-350 Four Wheel Drive Manual 155k miles

Speedometer stoped working.Where does it connect to manual trans ?

Yes. Let's pursue a little further. Becuase they all go out at the same time. Cruise, speedo, odometer, etc. Also, they have come back on on occasion too. When the speedo is back, the cruise is as well. I would like to pursue further. Tell em what to do.

It doesn't connect to the transmission at all. It reads off the ABS speed sensor located in the top of the differential but if you don't have an ABS light on, the problem could be elsewhere in the electronic circuit.

It may interest you as well, I just plugged everything back in a test drove the truck real quick. The speedo and odometer, everything was working for about 2 miles, then it went out again. Is that possibly because I disconnected the batteries and reconnected them. Did a computer reset itself, or something like that?

I have the GEM module in front of me. It looks to have no water damage, but it is very dirty. Is there some way to test it? What should I do next?

Are you available on saturdays?

Okay, I found were the GY/BK wire splices into three but it is very hard to get to. It is underneath the Power distribution boxand master cylinder. Is there any way to test them at a further site that may be easier to get to? Also, I will not be around much tomorrow so don't worry. I will be working on it off and on through the weekend, and I will email you when I do something else. I would like to hear your thoughts on the wires in a different location and any further steps you can give me to do on my own over the weekend that might help to narrow down the location of my problem. Thanks again for your help on your own time. Talk at you soon.

i have a 99 f350 with the v10 and im having trouble with my speedometer. it seams to stick between 10 and 35 mph, sometimes it does it when im starting out and other times it will drop down when i am driving. i have tried changing the speed censor, flushing the rear end, the tranny, and now im out of ideas. any suggestions?

Hello again, I have not written in a couple weeks because I thought I had my truck sold, but it fell through. So I am back to working on my speedometer. I finished doing what you last instructed me to do. I tested the integrity of the grey/black wire that comes from the ABS module and splits into three. The integrity is good all the way to the three plugs. By that I mean, at the plug that goes into the PCM and the plug the goes into the speedo cluster, and the plug that goes into the fuse block/GEM. Now, I know my cluster is good becuase it comes back on from time to time. How to I determine if my problem lies with my fuse block/GEM or in the PCM? I don't know if it helps but remember my cruise control also goes out with the speedo, and comes back on with it as well. And the O/D light is blinking, and the code was for the vehicle speed sensor. Sound like the PCM is faulty?

Check the wiring if okay -investigate the speedo assy in dash

Have you tried to smack the dash above the cluster when it sticks to see if it effects the speedometer?

thanks i will check those things. i dont think its the cluster though because hitting the dash has no affect on it.

Your welcome keep us posted.

speedometer doesn't work and tranny shifts with a harsh head snapping jerk. i replaced the vss sensor on top of rear axle, but problem still exsists. help please. thanks, geo

You changed the speed sensor for the abs not for the speedometer.What code's do you have?Go to the auto part's store like auto zone and see what code number's you have in the computer.

is the odometer still working properly? the VSS gear itself may be bad and not the VSS.

My speedometer quit working and now every time I drive the truck and the speedometer needle starts to move it blows the #8 fuse. I checked everything else on that circuit and it seams to be fine. Please help?

There has to be a short between the fuse and the speedo or the VSS is bad. Have you checked the VSS?

What is the vss and where is it located? Thank you for all your help.