'95 F 150 4x4 4.9l auto trans auto hubs 31x10.5 x15 tires

I lost my speedometer and the odometer ,the trans shifts HARD from first to second (as like getting hit in the rear)
i was told it was one of the censors, either the one on the trans or the diff and it put the trans in "limp home mode"
if the one on the diff is bad it also has the ABS censor (but no lite in dash for ABS).brakes are fine
would that mean the one on the trans is the problem?
thanks ken

 

There is no sensor on the trans. The VSS on top of the rear axle is the one and only speed sensor on your truck, and provides data to the PSOM as well as the EEC, ABS, cruise, and speedometer head.

Most likely (but NOT definitely) you have a bad VSS or dead PSOM. Gotta run or else I'd help you troubleshoot... someone will step in and explain how.

 

The sensor is more than likely OK and not your problem.
You either have a fuse bad or a bad PSOM in the cluster.
I say this because you said you also lost your odometer and your RABS light is not on.
The sensor has nothing to do with the odometer being on or off.

If you change the sensor you may be opening a bigger can of worms.

Check the fuses first, #8 & #18 in your cab fuse panel.

 

2X on what Subford said.

If one of those fuses is blown(fuse #8 I recall) check your dome light for shorts! The plastic in the dome light will melt over time and blow the fuse causing the PSOM to go dead and the ECU to put the tranny in to limp mode.

 

Isn't it weird what is wired to what in these trucks? I'm glad there is this place with a collective of diagnostic history to back each other up. What a blessing!

 

How true! I have been a electronics repair tech over 20 years and still wonder why engineers do really stupid things. I have always said to be a design engineer , they should be a repair tech 1st, to see some of the stupid things.......and learn how to design it better/smarter.

 

X10 Eddie, X10!

 

Agreed. With my job, I started out building industrial control panels and now I mostly do programming, although I have designed complete control systems start to finish. The stupid things I've seen other engineers do when I was a shop tech definitely get taken into consideration when I do my work. Makes life easier when somebody else screws up for you!

I just hate how on several Fords I've owned, that you look at the fuse chart by the panel and it says:

Fuse XX: (device), (device), (device)

and then fails to tell you that there are OTHER things on that circuit which ain't even listed. Not even a hint that there might be more to it than the chart shows. You gotta dig out a schematic and trace it out to find out the whole truth. Retarded.

 

I worked on a couple of newer Ford vans few years ago. It had a main fuse that led to another fuse which again to yet another fuse!

What got me the fuse in the middle was ONLY a 10amp fuse! The last one was a 20amp fuse!! I verified that with another same year truck and owners manual. What were they thinking.......

 

I just found out my number 18 fuse was blown. it is top right corner of the box. Fixed my speedo and odometer up! If it keeps blowing, check your airbag diagnostic module (under the steering wheel). You can unplug it and see if the fuse still blows. If you do, though, stay clear of the airbag while messing with wires. I think it's safe, but I wouldn't risk it.

 

ok,guys , sorryI have not gotten back to you, as you can see here
I have a problem with my garage..............I DOMT HAVE ONE
2-6-10snow010.jpg Photo by woosterken | Photobucket

but it got up in the 50s today and the ole man was able to get out to the truck CUBBER
you are right it is the #18 fuse,I replaced it ,and the odometer came back on (but it blew it again ) as you said it was marked speedo /air bag but I think I will take it in to ford to let them mess with the airbag, that thing scares the snot out out of me
is the diagnostic module in the colum ,or does the wheel have to be removed?

 

I believe the speedo fuse also handles the domelight, and the wire running up the pillar often chafes and shorts out.

 

That's the #8 fuse.

 

1st if you have shift on the fly I think I would look at that first as the cause of your fuse going bad. Maybe a bad TR sensor or the wiring around it on the side of the transmission.

2nd I would look at the shift lock wiring as being bad in the column.

3rd unplug the air bag module and see if it still blows.

4th then of course the PSOM but I have not heard of the PSOM blowing a fuse.

 

ok, guys sorry for not getting back sooner took my truck in to the shop.
they checked it all out,and said the air bag module may be bad ($200.00)
what they did for me is REPLACE fuse #18 for the speedo/odometer and REMOVED #8 which disarms the air bag module , but lets the speedo/odometer work and allows the trans to shift right .
I used new fuses from auto zone that has an l.e.d lite in it that comes on when it is blowen out mechanic says they are JUNK!!
so if you have the same problem as in my first first post this should help you

ken