Speedo problem

hi there. I am in need of some help figuring out what exactly is wrong with my speedometer. It doesnt work much at all. Once in a great while it will work for about a half a mile then it will quit, start working again for a second, and then quit for good. I have tried the vss. Just wonderin what you guys think i should try next. My cruise works properly. I seen in a search about the abs. My abs light is on but it is because the fuse is pulled. when the fuse is in the speedo still doesnt work. But the abs is messed up thats the reson for it being pulled. any ides please shot em my way. and sory for the long post just trying to be thorough. thanx guys.

Welcome to this forum! You might have a defective gauge.

Welcome to Explorer Forum! It could be that the speed sensor is bad. I would start with that and it may even help with your ABS. If it is NOT the sensor, then move on to the gauge.

The 95~97 Ex rear diff ABS sensor does not affect the speedometer at all for those years. Instead, the VSS signal for the speedometer/speed control/PCM comes from a gear driven Signal Generator on the transmission or transfer case.

If your cruise works well, then it doesn't seem possible that the Signal Generator or its gears could be bad. That just leaves the branch circuit to the cluster or the speedometer itself.

On his 97, if the cruise control works, it's not the VSS. The VSS signal is sent to the speed control servo, GEM, Instrument Panel, Message Center, ARC Module, and outside air temp module. If the VSS was shot, the cruise would not work.

I'd be looking at the gauge too. That's where my money would be. When the gauge doesn't work, does the odometer keep rolling? If so, then you know that the correct signal is getting to the IP, it's just the gauge that's not working. If the odometer quits too, then it's probably the signal coming to it.

Make sense?

this is the exact problem i have on my 97--

speedo/odo stops working after a few minutes of driving.
cruise control still works, even when speedo/odo quit.. and vss has been replaced. i traced all the connections from the vss to the firewall in the engine and they all seem fine.
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if there is a bad connection in the "branch circuit." where does this circuit split begin and what path does it take to the ip cluster?

If the only problem you are having is the speedo, then, if it is indeed a wiring problem, it has to be between splice S247 and the cluster. That splice is located under the dash and feeds the GEM, Message Center, Overhead Console, Air Ride, and Instrument Cluster. The cruise control and PCM are fed from a previous splices under the hood. So it is possible you could lose the signal out there, and still have the car run normally if you don't have the Message Center, Air Ride, etc. I'm not sure what would happen if you lost the VSS to the GEM unless you were using something that required it.

If this were me, I would round up a meter than can read the VSS signal and start testing locations once your speedometer quits. You are looking for a gray wire with a black stripe.

is splice 247 located behind the radio cover, on the black box that has multiple connectors coming out of it behind the dash?

Did you ever resolve this issue? I'm having the same problem on my 97 5.0L explorer. Like others I swapped the VSS with one I had on hand. Did not change anything. Cruise control works fine. Speedometer/odometer works intermittantly.

I am hesitant to replace the cluster. The problem seems to have some relation to temperature. Also if we leave the house it drops off at nearly the exact spot on the freeway everytime. Not quite what I'd expect from flakey electronics.

Does anyone have an EVTM for this year explorer?

I've seen several people complaining of the same problem, but no resolutions.

Welcome to this forum! I see that you've joined many years ago, but this is your first post. Check this link: http://www24.brinkster.com/sdhartney/linc/linc.htm

baddriver said:

is splice 247 located behind the radio cover, on the black box that has multiple connectors coming out of it behind the dash?

Click to expand...

i was wondering the same thing.. is that s247 located behind the radio or the one right above the foot brake?

i still havent resolved the issue.. dont know where this splice is at

I have a similar problem... 97 EX 2x4 4.0L V6 - tripping 0720 (output shaft speed sensor) O/D flashing, no 5th gear or overdrive, 2-3 flare.
1. Found VSS wires nicked so I cut and crimped - Speedo still works, Still tripping 0720
2. Replaced speedo gear to adjust to correct speed - speed fixed but still tripping 0720
3. Replaced VSS - Speedo still works, Still tripping 0720
4. Adjusted Bands - Speedo still works, Still tripping 0720
After reading as many post as i can find and working with Brooklyn to get these steps all done I believe I have a wire/short issue? In several posts and manuals I read the following:
1. Check Pin 3 and 6 for the VSS
2. Radio gets VSS for Auto Vol Control (AVC)
3. Box is located behind the stereo
My questions:
1. Where is the box that has pins 3 and 6 i should test to ensure I have continuity from the VSS to the far end?
2. Is it possible a short in the Stereo (occasional pop in the speaker and rare AVC changing the vol to Max for no reason) VSS signal is the culprit or just related to a bad VSS signal?

Walldingo said:

I have a similar problem... 97 EX 2x4 4.0L V6 - tripping 0720 (output shaft speed sensor) O/D flashing, no 5th gear or overdrive, 2-3 flare.
1. Found VSS wires nicked so I cut and crimped - Speedo still works, Still tripping 0720
2. Replaced speedo gear to adjust to correct speed - speed fixed but still tripping 0720
3. Replaced VSS - Speedo still works, Still tripping 0720
4. Adjusted Bands - Speedo still works, Still tripping 0720
After reading as many post as i can find and working with Brooklyn to get these steps all done I believe I have a wire/short issue? In several posts and manuals I read the following:
1. Check Pin 3 and 6 for the VSS
2. Radio gets VSS for Auto Vol Control (AVC)
3. Box is located behind the stereo
My questions:
1. Where is the box that has pins 3 and 6 i should test to ensure I have continuity from the VSS to the far end?
2. Is it possible a short in the Stereo (occasional pop in the speaker and rare AVC changing the vol to Max for no reason) VSS signal is the culprit or just related to a bad VSS signal?

Click to expand...

For 97, the OSS sensor and code P0720 have nothing to do with the speedometer.

The OSS supplies output shaft RPM to the PCM for transmission control calculations only. Look for the OSS on the DS rear of the transmission case close to the top (dark blue/yellow and gray/red wires).

The speedometer, radio, speed control and PCM all get vehicle speed information from an AC signal originating at the VSS signal generator in the DS of the tailhousing (gray/black and pink/orange wires).

rwenzing said:

For 97, the OSS sensor and code P0720 have nothing to do with the speedometer.

The OSS supplies output shaft RPM to the PCM for transmission control calculations only. Look for the OSS on the DS rear of the transmission case close to the top (dark blue/yellow and gray/red wires).

The speedometer, radio, speed control and PCM all get vehicle speed information from an AC signal originating at the VSS signal generator in the DS of the tailhousing (gray/black and pink/orange wires).

Click to expand...

can you explain DS, I'm drawing a blank, Thanks for the answer

Thanks RWENZING, found the connector with the wires you mentioned, and nowhere to plug it in... now the rest of the story... Have been told by a tranny shop I have a 4R55E instead of the 5R55E that's supposed to be in there. Nobody could tell me how to verify that since the body is basically the same and their is no tag. I read on another post that there was a wire for the Overdrive speed sensor on the 5R55E (vice Output Shaft Speed sensor) that was no longer used (was only used short term and later abandoned) so it was to be cut and soldered together (verified that with the tranny guy at Ford). I assumed that was the same wire so it didn't concern me and I jumped it closed with no effect. If you're saying it should be connected could the solution be to jump the VSS to the OSS connector?

Walldingo said:

can you explain DS, I'm drawing a blank, Thanks for the answer

Click to expand...

Sorry, DS=driver side.

Walldingo said:

If you're saying it should be connected could the solution be to jump the VSS to the OSS connector?

Click to expand...

That almost certainly will not work because the frequency and pulse type are totally mismatched.

Your 97 PCM software set up for the 5R55E needs the OSS input that was not present in the 95/96 4R55E transmission.

rwenzing said:

Sorry, DS=driver side.


That almost certainly will not work because the frequency and pulse type are totally mismatched.

Your 97 PCM software set up for the 5R55E needs the OSS input that was not present in the 95/96 4R55E transmission.

Click to expand...

Heres some pics. Looking at another post of the 4R70W OSS I'm assuming I found where it should be. There is a cap over it, it is loose as if it could be popped off. I didn't see or feel where a bolt would go to hold in another sensor.

This is why I thought the wire was not a factor...I take it the ODS is not the OSS as I had thought?

Article No.
97-15-28
07/21/97
TRANSMISSION - 5R55E - OVERDRIVE DRUM SPEED SENSOR DELETED -SERVICE TIP.
LIGHT TRUCK:
1997 AEROSTAR, EXPLORER, RANGER
ISSUE:
The Overdrive Drum Speed (ODS) sensor has been deleted as a running change. This may cause the Powertrain Control Module (PCM) to receive stray
signals from the non functional ODS sensor that may affect the operation of the transmission.
ACTION:
Disconnect the ODS sensor connector, cut off the connector end, and splice the wires together. This should reduce the possibility of stray signals
affecting the operation of the transmission. Refer to the following Service Procedure for details.
SERVICE PROCEDURE
1. Disconnect the ODS sensor connector from the sensor.
2. Cut off the connector end.
3. Splice, and solder the two (2) wires together.
4. Shrink wrap the wires, and secure the wires to the harness. For proper wire splicing techniques, refer to the Augat Connector Repair Kit Manual.
5. Leave the sensor installed if using the original case. New service cases will not have an ODS sensor hole in the case.
PART NUMBER PART NAME
F77Z-7005-DD Transmission case
OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS: Eligible Under The Provisions Of Bumper To Bumper WarranW Coverage
OPERATION DESCRIPTION TIME
971528A Eliminate Overdrive Drum 0.3 Hr.
Speed (ODS) Sensor
Connector As Outlined
DEALER CODING
CONDITION
BASIC PART NO. CODE
7005 12
OASIS CODES: 501000, 502000, 504000

If there is no place to install an OSS as I suspect (unless it will fit in the capped looking location in the pic) and jumping the VSS signal to the OSS won't work, would the RABS signal work connected to the OSS cables?