Guys I'm so sorry it took so long to reply. The fine weather came in and of course I had to have (minor) medical issues but nonetheless enough to stop me from working on the (nappa)truck.


Anyways, I did manage to get out underneath and fiddle with the sensor. I got the bolt out (lots of room but I'm pretty bulky so it took way longer than it should have) but could not remove the plug/clip and I worked at it until one of the clips broke off. Any suggestions from you fine folks?

Thanks to the tax gods I'm in a position to get my truck fixed and I'm heading out to grab the parts today. Thank you guys for all your input. The diagrams were fantastic

 

Great! Good luck on your repairs, Brad! Keep us posted on your progress.

Roger

 

Thank you for the kind words

BTW your truck looks awesome. I have no idea why Ford went with those plastic mirrors that I'm stuck with. Good thing there are a ton of 90's F-250 at the pick a part

 

So the speed sensor finally came in and I rushed out to install it with the few hours I had left. Something I noticed is that the old sensor had a metal bottom that fit into the diff, the new one from Napa had a plastic one . The sensor was a major pain the **** to take out and the harness that was connected was corroded. I cleaned it up the best I could, installed the new sensor, connected the harness and....... Still shifting hard with the check engine still on. The cold forced me in for the night but needless to say, I'm bummed.


How does that new speed sensor measure anything with a plastic bottom? Where else do I go from here? The harness?

Literally every thing I've replaced now has had a corroded plug

 

I do not know why you replaced the VSS sensor. From all you said above it was OK and the speedometer worked OK as you said above in this thread.

Replacing the speed sensor very seldom fixes the VSS problem. I do not think I have seen a bad one yet. They get replaced a lot but the problem is still there as noted above.

But what does happen is when someone replaces the VSS sensor sometimes they brake the old one and that sounds like what you have done. There is still part of the old one in the rear end and that is why the old one had a metal bottom.

I think you said the speedometer needle was steady and no RABS light on in the cluster so that tells you the VSS sensor and its wiring was OK.

Most of the time the new VSS sensors do not work as good as the old ones from what I have seen on this Forum.

What is your speedometer needle doing now when you drive it?
More than likely not working at all now.

So now it sounds like you are going to go inside the rear end to get the broken part out.

When you get the speedometer working like it was you need to find out why the PCM is not getting a VSS signal train from the PSOM.
You may have a bad speed control module, try unplugging it and see if it shifts OK now.
Check the wiring from the PSOM to the PCM, it may be open or shorted to ground.

If all of that is OK replace the PSOM, it is a cheap $5.00 board at most pick & pulls as they will not know what they are selling you if you do not tell them. The PSOM is the same from 1992-1996 F-series trucks and E-series vans.
Then drive it and see if it shifts OK.

If not replace the PCM itself, less than $50.00 at most pick & pulls.
Then drive it and see if it shifts OK.

 

I'm don't think I broke the part off. Unfortunately I still can't upload pictures but nothing appears to be broken or rattling on the inside, there was just some metal shaving and gross grease on it. I cleaned it off and got the corrosion out of the plug. I'll be reinstalling tomorrow. I'm not so sure the vss is functioning due to the corrosion on the plug and on the harness. I'm going to trace the harness back to the bumper and hopefully a good cleaning will solve my issue.

My speedometer is still fine no wavering or surging and its still accurate up to 120km (fastest I travel) I noticed when first turning the key the odometer reads all 8's but a broken "6" like number. Perhaps another tick for psom?

Is the RABS light the orange ABS light on my cluster? That's the only ABS like light I can see. It lights up for while starting and turns off after a few seconds. While running the only light that's on is the check engine light. Thank you very much for your reply

**One more thing, I noticed while driving around today that if I gently lift off the gas at 20km it'll shift into gear smoothly if I reapply pressure a certain way, same thing when shifting around 40km. Not sure if it means anything just wanted you fine folks to know.

 

Then your rear end sensor and wiring is OK and not your problem.

It does not sound good for your PSOM. If you replace the PSOM board (not the speedometer head) I would love to get my hands on your old PSOM board to read (dump) the information out of it so I could see the difference between the ones that read out in miles vs km.

The ABS light on your cluster is for your RABS.

A PSOM board:


A PSOM board still attached to the speedometer head:


The PSOM location, but you take the Speedometer head out the front of the cluster and then remove the PSOM board from it:


/

 

Thank you very very very much. I'll be heading to the pull a part today and I plan on grabbing a few of those psom's and hopefully those pre 96 side mirrors.


If I can manage to get my truck shifting proper again I'd be more than happy to send you that PSOM!

Thanks again

 

The ribbon cable you just pull up on each side of the plastic and then the ribbon cable will slip out.
The screws that hold the PSOM to the speedometer head are removed with a T10 TORK screw driver.
The screws that hold the the cluster to the dash have 9/32" heads.
The screws that hold the faces plates to the cluster have 7/32" or T15 heads.
The gauges just pry out from both sides before the speedometer head comes out and it will just pry out also.

Also look at this how-to:
https://www.ford-trucks.com/articles...150-or-bronco/

/

 

For more information and my address if you need it just email me at the email address at the bottom of this post.

 

Hello again. I know its getting old but I've been delayed yet again. The weather has been cold and I know its an excuse but big hands don't get along with frozen plastic! I haven't forgotten about you Subford! I'll be picking up that psom in the next couple of days (warm weather)


I do have an update. Since I've put in that VSS from Napa my speedometer goes ballistic once I hit 70km. Which means that Napa VSS wasn't working in the first place right? Because I know for a fact that the factory one DID NOT do that. Either way the psom is the next to replace. I also notice that if I let of the accelerator at the right time its almost as if its in neutral and I have to completely let off the gas before it hard shifts into gear. Its pretty random and the local jiffy lube told me my tranny fluid looked fine. Please tell me you think this is because of my bummer PSOM.


Another question if I may subford since I'm beginning to really value your opinion. . Someone (never met, friend of a friend) suggested that I swap out some sensor IN the transmission and that will fix my issue. What do you figure? If there was some faulty sensor in my transmission wouldn't that give me a code?

 

I replaced my VSS with one from Autozone and it caused the same problem of the speedo bouncing around. I forked the money up and bought a VSS from the Ford dealer and it went away and no more codes. Sometimes you can't use the aftermarket parts they just don't work.

 

No there is no sensor in the transmission that will give you the VSS code. He is thinking of either newer trucks (1998 and newer) or trucks that are older than 1992.

The only sensor on your transmission is the TR sensor that is mounted on the drivers side of the transmission. It can cause hard shifting but it can not give you a VSS code.

 

Did the one from the Ford dealer have a metal bottom? I noticed my old one carried a magnetic charge. The new one I bought doesn't

 

Hello again, Sorry I've been away for so long. I've been so busy with work that I've never had time to respond, however today was payday so I get to buy some parts tomorrow!


I have a few updates for Subford (Thank you for your help) and all the other helpful folks who are kind enough to share their information with a chap who really appreciates it.

After my last post I scrapped my dash and inspected the psom. Everything *looked* to be in order which at the time. I headed to a pick a part, found a match truck and partook in a job that took way longer than it should that yielded a psom with a blown capacitor. I checked at the dealership and its $650 for a new cluster no chance at getting just the psom. As much as I love my truck that's too much for the sake of a $8 PCB. So I've been living with what I have. Since my last post I've changed my oil, and swapped my plugs and fuel filter (had trouble starting) and I plan on changing the tranny fluid (finally!) tomorrow. My truck has pretty much been running the same ever since.

I plan to take my truck in for a proper visual diagnostic by someone who has many more years of experience than myself but there is a question I'd like to ask:

I notice sometimes my lights (external, brakes, indicators) are failing to turn on. They still work, just sometimes and today on my lunchbreak my speedo and tach didn't work until I gently smacked my dash (don't know why I did that, instinct I guess) is there a chance that this godforsaken corrosion (that seems to be on every plug) is causing my issues? I'm still open to grabbing a psom when one becomes available but until then I'd like to clean that corrosion off in the meantime.

Another silly question but how would I do this and what tools would I use? the ol' toothbrush and wd40 isn't working too well, which is the best way to pry the plugs apart? They feel like they're fused.

One more thing, I'd like some opinions and/or life advice. I know its difficult to rate a truck without seeing it but at this point will that investment be worth it? I'm looking at $500+ for fluids $277 for a rad, suspension, eventually new exhaust, click in the steering, no stereo, soon to happen termclad paint job, new box, hours and hours of time, fused plug connections, a brutally hard shifting tranny, a minor leak in the rear seal and the lack of still functioning electronic parts is becoming very very startling. I love my truck and it has a great engine but should I be spending the money on this or should I just sell it off/project it and buy something else? It's a physically solid (still) truck that I only paid $650 for but if you guys were in my shoes what would you do?


Thank you all again