It looks like they go into those two snap connectors.
Can not tell the wire colors of the wires the snap connectors are on but I would guess that they are turn signal wires.

 

Hi,

I'm new to this board but am going through a nearly identical situation (with the speedo) and have used this post and another few to t/s a few things. My issues surrounding this are as follows:
New truck (to me), 248000 on it, 95 4x4 5.0. Problem started about a month ago. ABS came on and speedo was all over the place, but within about 10mph of actual. Then it all stopped when I replaced the ABS fuse (blown). Yay, I'm all good, right? Speedo is intermittent and problem is on/off again.

Just took a trip about 500mi each way. On the way down, I noticed that it was hard to move from a stop at times. Like the parking brake was on (which I now notice the indicator light is not working). Also, a couple of times on the way down the truck felt like it slipped or the rear brakes went on just for a moment. But only when the speedo was going nuts, which fortunately only happened for about 10 mins or until I turned the truck off.

So, needed a clutch anyway while visiting family, so I got a good deal on all that stuff, they checked the rear diff and it was low and nasty but nothing too hardcore. Truck was just fine until about 350mi into the return trip, and speedo goes nuts again. BUT, I could stop, turn the truck off, back on, prob gone. Now the speedo problem happens constantly. And it's sometimes tough to get going from a stop.

Replaced the VSS today, same problem. No shavings, just some blackish oil on it. Checked wires, all good. Unplugged the ABS behind the glove box as I saw in another thread, no change. All fuses good. Odometer works fine. Again no parking brake indicator light. Also, truck seems to want to stall about 2ft into rolling forward or reverse and I have to give it about 150% of the gas I normally would to overcome that. Which can't be good.

I had a shop check the diff as I said, and they said it looked good. Then again, they also forgot to connect my 4wd lever when done (I have nothing good to say about that). No metal on the old VSS, but the top 1/2 of the sensor was yellowish (like overheating or something) so I figured a new one wouldn't hurt too much. I don't like autozone, but it's all I have here as I am a solid hour from the dealer and after hearing about the tranny pressure issue which might be happening, I'm a bit freaked out about my last trip and don't want to go too far to figure this darn thing out.

Well I hope this helps a bit. Thanks to all that have helped me so far without knowing it.

 

I would say you first step is to see if there is a code.
If you have a code post it back here and we will try to tell you what it means.

Here is how you check to see if you have a code:
Diagnostic Trouble Codes, Retrieving

NOTE:
Verify the ignition switch is in the RUN position (engine does not need to be running). Next, locate the black RABS II diagnostic connector. The diagnostic connector has two mating halves (one of which has a black/orange wire connected to it). Disconnect the two halves.

Attach one end of a jumper wire to the black with orange stripe wire side of the diagnostic connector. Momentarily ground the opposite end of the jumper wire by connecting it to a good chassis ground for 1-2 seconds. Grounding this wire should start the yellow REAR ABS warning light flashing. If grounding this wire does not start the yellow REAR ABS warning light flashing, go to the Symptom Chart.

CAUTION:
Care must be taken to connect only the black/orange stripe wire to ground. Connecting the mating connector wire to ground will result in a blown fuse.

The code consists of a number of short flashes and ends with a long flash. Count the short flashes and include the following long flash in the count to obtain the code number. For example, three short flashes followed by one long flash indicates diagnostic trouble Code 4. The code will continue to repeat itself until the key is turned off. It is recommended that the code be verified by reading it several times. This code will be used later for system repair instructions. It should be written down for future use. A diagnostic trouble code of 16 will be obtained when the anti-lock electronic control module detects normal system operation.

 

Code 16. 15 short flashes followed by 1 long one, right? That's good and bad, no? Also, while under there I noticed that there isn't anything plugged into the PSOM connection beside the diagnostic connection I just used. Also, there is a 5 wire 6 pin connection directly below the ashtray that isn't hooked up to anything. I have the bare boned XL, so I know there are unused connections on that harness but just want to report it in case it helps the cause.

 

That would be code 16. Yes that is good, 16 means no codes stored.
That is the OK, you only use it to change the tire size.
That is for the brake controller.

 

Sounds good so far. Thank you, subford. I was really crossing my fingers that you might be able to help a bit. So do I need to check the circuitry behind the speedo (PSOM) at this point like the guys in previous posts?

 

I am not sure what your problem is.
Most PSOM problems effect the speedometer read out, the speedometer, Speed control and transmission shifting. If it is the PSOM it would have to be shorting the VSS input and I would not think that would be to likely.

The RABS is ahead of the PSOM but the RABS was made to release the brakes with a dump valve, not put them on.
But you may try unplugging the RABS module and see if the problem goes away.

It sounds like you have a brake release problem with the Master Cylinder, shoes or wheel cylinders.
Or it could be wheel bearings also.

 

I thought of the brakes right when the problem went from bearable to worse. The thing is, when the speedo works, all is good. When it doesn't, I have a hard time shifting into 2nd (manual tranny) among all the other stuff that's wrong. We have a storm rolling in now and I have no garage, so I'm finished until next week after I get back from visiting family. That might give us some time for a few others, including the OP, to get back and start hashing out other options. I'll look around when I get back to see what else might be loose, cracked, out of place, etc. I will also disconnect the RABS module and check the wheel sensors like 97FRD did to see if lightning can strike twice...

 

You do not have wheel sensors

 

Something else to think about: This Speedometer/Odometer problem has happened not too long after getting the cruise control recall done. I don't know if there is any correlation.
I still haven't had a chance to look at my further since last post.

 

The recall just added a fuse to the brake pressure switch on the MC and maybe replaced the brake pressure switch.
It had nothing to do with the Speedometer/Odometer system.

The Speed Control module if it is bad can keep the transmission from shifting right on the Automatic Transmissions trucks (no VSS input to the PCM Computer).

 

Well today went to the junkyard to get a gauge cluster for my son's piece of junk 92 Nissan Sentra. First the Temp. and gas gauge went out. Then 2 months later the Speedo/Odometer went out. Got the one from the junkyard for $28. Put it in. The gas and temp. gauge now work. But, still no speedo/odo. It is the speedo cable type, and the cable is not spinning. We drove it without the cluster to see if it would spin. So it has something to do with the cable.

But; while I was at the junkyard; I obtained 2 more PSOM's just to see if the replacement I got before was not working. They were only 17$ a piece, and carry a 30 day warranty. So tomorrow I check with the junkyard PSOM's. Wish me LUCK!

 

IT'S FIXED!!!!!!!!!!!
IT WAS THE PSOM ALL ALONG!!!!!!
The new junkyard PSOM fixed it! As I posted yesterday, I got 2 of them. Both of them worked! One of them only had a 2k difference in mileage! The only problem is that it is obvious that it had different size wheels. It came from a 96 F-250. I need to calibrate at some point. There seems to be almost a 5-10 mph difference. My 95 F150XLT has 15 inch wheels. The other PSOM I got yesterday was from a 92 XL styleside in near perfect condition. But, it has 212,000 k on it. The 96 had 172,000 k. Mine has about 169,000 k.

On a side note on my son's 92 junk sentra: the speedo cable is broken so it may be an easy fix. It broke right where it meets the speed sensor.

Thank You to everyone who helped me! Especially Subford!!!! Thank You X a billion!
I learned a lot, and that's what I enjoy.

The moral of this is: Get an extra PSOM or 2, because they seem to break.

The broken PSOM's I have, if I have time, I may reverse engineer; and see what I can figure out. It would be helpful to be able to repair them.

 

That is great that you got it fixed.
If you do reverse engineer it please let me know what you find out.
You might want to read this PDF also:
http://7pt3powerstrokediesel.com/lit.../2007_1_04.pdf

/

 

Wow! That was a great read based on what I have been going through. Something interesting in the article: Was the truck in the article was not upshifting properly. When I first got my truck, it wasn't shifting properly. After replacing my cooling system, the problem went away for the most part. I thought it might have had something to do with temperature, as the truck was near overheating before I replaced the cooling system. Once in a blue moon, my truck doesn't shift properly still. But the problem quickly goes away. Something else interesting in the article was about a possible internal short in the cruise control module causing a problem. My cruise control has not worked since I got the truck. I don't know if there is a relationship there either. It seems there are a lot of people on here who have cruise control problems also. I have not had the chance to really try and fix my Cruise control quite yet. It's on the list of things to fix, but kind of low on the list. Brakes and front suspension are next! There was another thread in another Ford Truck Board:
https://www.ford-trucks.com/forums/1...lem-fixed.html .

I know this is not the same as our PSOM, but I believe the problem is similiar. I really believe this, because my problem started after a freeze outside. I carefully inspected the PSOM with a magnifying glass, and couldn't notice anything. Of course, I don't know too much about circuit boards; so I don't know if there is something wrong right in front of my face. I didn't notice anything physically burnt, loose or leaking. But, again it doesn't mean that I just don't notice. I really want to find a way to fix these PSOMs. Too many people seem to have the problem. There's got to be a simple fix.

I forgot to add that I have been having another electrical problem that was draining my battery. I recently replaced the grounding so I thought that I did something wrong, and was going to go over what I did. I would have to hook up a battery charger for about 10 minutes to get the truck to start. My son noticed the glove box light was on. I've had the glove box detached while working on the speedo/odo. problem, which left the light on. I'm willing to bet that this is what was draining my battery.