Speedometer not working

Hello,

It sounds like the PCM went bad but to be sure lets do a wiring check between the VSS and the PCM. Here is a guide to help us and the engine and transmission wiring diagrams so you can see how ti works and which wires to test. Check all fuses as well.

https://www.2carpros.com/articles/how-to-check-wiring

If the fuses and wiring checks out I would try a used/rebuilt PCM. Check out the diagrams (below). Please let us know what you find. We are interested to see what it is.

Cheers, Ken

Will do, I will let you know the results this weekend.

Please do.

Did a recheck on wires and found the wires to the ABS sensor on the rear differential broke. I fixed them and the ABS light overdrive light both went off but the speedometer works fine until you reach 50 mph then starts bouncing around like crazy. Gas gauge still does not work. Thinking sending unit, needle moves from full to well overfull when I turn the key on transmission still has a pretty firm shift and shutter from time to time on the highway.

Maybe filter fluid change on transmission?

Is the VSS sensor OEM? I would install the old one if not. Cheap sensors can make the needle bounce. It does sound like the fuel level sensor for the fuel gauge issue. To confirm the issue remove the fuel gauge wires and ground it, (yellow and white wire).

I cannot find a yellow and white I have a brown and white and yellow and green. Then an redish orange and thick black. I assume those are fuel pump, the other two wires give no signal on my meter, and gauge does not react when they are grounded.

Oh, put the original VSS back in and all other problems fixed. Speedometer and odometer work fine. ABS light is off and she shifts normal. Thank you for the help. All that is left is gas gauge.

Gas gauge repaired, I bypassed the yellow and green wire and the gauge started working. Every issue I had was faulty wiring.

Glad you could get it fixed, that kind of problem can be tough. Please use 2CarPros anytime we are here to help

Cheers, Ken

The speedometer in my truck is not working properly. It will work fine until it reaches 35-40 mph, but then starts jumping around. The odometer seems to be working correctly. I have replaced the differential sensor, transmission sensor and speedometer head with no luck. The truck has been sitting idle for about a year. Any help would be appreciated.

This could be a wiring issue or the item in the picture which is an amplifier for the speed sensor not sure if a scanner will pick that up or not. See picture.

Checked wiring and all seems okay. Any way to check amp? Could a bad ground to dashboard cause this? Thanks.

I guess the ground could as well as a bad or poor connection maybe at cluster. Never really thought about it. But if the amplifier was not working or had a bad ground it might do it as it would get a ground then send the signal then not. It is almost twenty years old so it could be a bad ground from battery considering the age of it. Or one that is supposed to be there and is not or it can even be dirty battery terminal ends. That is about all I can think of. Check the fusible links in pic they should have power on both sides same as battery and wiggle them around to test as it may have just a few strands attached and not making good contact that may do it as well. Kind of hard to figure out without seeing it.

My 95 ford was running along fine on a sunday night. It snowed, I did'nt drive it again till Tuesday. Suddenly my Tranny was shifting extremely hard from 1 to 2 and moderately hard from 2to3, My power door locks stopped working, my speedometer stopped working, and my dome light stopped working. Mechanic told me to try speed sensor, bought one, that part may be on my truck but it sure aint on my tranny! Tried replacing ABS sensor. Took my rear diff cover off looking for some sensor that my dads bronco has in there and had been replaced for same probs. Dont have one! So my questions are this, Could it be a fuse or rheostat? Something in the main power distrubution box? And where in the Heck is my speed sensor located? Somebody that had the truck before me installed electric fans, poorly, we had to rig a switch for them so maybe he messed up something else? He went through Power ditrb box. Also dont know if this makes a difference but the truck is a 95 built 10-94.
Any ideas? Please help, layed off mom with 3 kids! Really tryin to fix this myself!

The truck ran all right until it snowed, could soem wires have gotten wet and shorted. Check the battery connections and clean if needed. Also check the ground wires. Some look all right but are not getting a good ground. With everything stopped working after the snow, that what I would think happened, I don't see why the transmission, the door locks, dome light, and speedometer would stop all the same time unless something happened to the electric. Make sure the fuses are good after checking the connections. There should also be a fuse box by the front fender under the hood.

Thanks so much! I will check those things. I had already decided it had to be electrical as I noticed more n more things not working. Had suspicions of the power distribution box. Now I will also check on wiring! Thanx again!

My speedometer does not work. I have been told that Ford used an electronic speedometer in this model. The fuse is good, there is a plug at the bell housing with no apparent place to connect to. Shouldn't there be some sort of additional wireing or conection there?

I can't tell without seeing the wire. THere is a speed sensor on the transmission that is most likely the problem.

I started my truck up one day and found that the speedometer is not working, the digital mileage display is not working, and my over drive light on the gear shift (automatic) is flashing. What could be causing this problem?