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Hey there. I dont mean to bring back a old thread, but thi sis the exact same problem I am having on my 95 Big Bronco. Its been in storage for a year waiting on me to rebuild motor. So I just rebuilt it and got it working great. Now the engine runs great and the transmission shifts rough. The speedo and odometer dont work. I have no check engine light, no ABS light, everything works on the truck. ALL fuses are good, none ever blew. The only light is the O/D light on the shifter blinks. So after lots of reading, I think its the PSOM. Please let me know what you think. Thanks
 

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Here's the schematic of the VSS to PCM, it sounds like the VSS signal is not making it to the PCM. That could be the reason that the trans shifts so hard.
If the signal is not getting to the PSOM, then that could be the reason the speedometer is not working.
Sometimes just pulling the connectors and cleaning them helps on these old trucks.



http://www.supermotors.net/registry/media/1041065
 

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yo s,
This problem could be caused by a # of things as Mikey advised.;
bad vehicle speed sensor (VSS) (also called ABS,, DSS sensor) on the 8.8 (rear differential)/ or Connector/corroded wires inside connector;
or cruddy/damaged tone ring in the 8.8.
bad 4WABS Module - It is located below ws wiper fluid/coolant recovery tank. So, the connector can be corroded by leaking fluid
bad PSOM (Speedo)
bad wiring/shorts /connectors from VSS at firewall, at 4WABS Module and /or at PSOM and then onto the PCM

The locations of the connectors along the path from VSS to 4WABS and up to Instr Cluster & PSOM are;
C404 VSS On rear axle sensor (A7) Terminals: 02

C205 LH rear of engine compartment, in safety wall (Fire Wall) Terminals: 24 In-Line

C202F & M LH rear of engine compartment, in safety wall (A8) Terminal: 7 In-Line

C119 LH front corner of engine compartment on 4WABS control module (E10),Terminals: 40

O/LB to:
C202F & M LH rear of engine compartment, in safety wall (A8) Terminal: 7 In-Line

C252 Programmable Speedometer/Odometer Module (PSOM), Behind top LH side of I/P, on PSOM (A7) Terminal: 12 Color: B at Pins 4

LG/Y to Splice S107 Engine control sensor harness, from C119 near T/O to G101 (G101 RH side of Radiator support); to PSOM Pin 5
C202 F and M
and spliced to Ground G100 (BK)
G100 & G104 (tied together in diagram) G100 @ LH front of engine compartment, on upper radiator support

G100 Serves Component:
Fuel Pump Module
Inertia Fuel Shutoff
Misfire Sensor
Misfire Sensor Shield
Output Shaft Speed (OSS) Sensor
Powertrain Control Module (PCM), 5.0L

G200 Behind bottom of RH cowl panel
Serves Component:
Air Bag Diagnostic Monitor
Electronic Shift Control Module
Instrument Cluster
Programmable Speedometer/Odometer Module (PSOM)
Remote/Keyless Entry Module
Speed Control Servo/Amplifier Assembly


From PSOM Pin 7 (GY/BK) to Splice S246 Main harness, near T/O to speed control amplifier to
C185 PK/O @ PCM 5.0L Powertrain Control Module (PCM) LH side of safety wall, on powertrain control module (PCM) (C10) Terminal: 104 Color: GY
C185, 5.8L Powertrain Control Module (PCM) LH side of safety wall, on powertrain control module (PCM) (C10) Terminal: 104 Color: GY

C185 @PCM to C202 F and M

and on to C185 @ PCM PIN 58 (GY/BK) and from Pin 46 to MLPS (TR) Pin 2
Verify PCM & MLPS wiring & Pin numbers using WIRING DIAGRAM by MIKEY

Speed Input Signal Test @ PSOM in 93-96 Bronco; "...NOTE: Only wiring harness end of connector is to be probed. * Connect Rotunda Digital Volt-Ohmmeter 014-00407 or equivalent to Pin 4 (speed in ) and Pin 5 (speed in -). * Does the voltage increase smoothly and continuously from 0 to approximately 3.5 volts as vehicle speed increases from 0 to 48 km/h (0 to 30 mph)? OR: If available, a frequency counter may be connected to Pin 4 (Speed in ) and Pin 5 (Speed in -). Does the displayed frequency of the signal increase smoothly and continuously from 0 to approximately 667 Hz at approximately 48 km/h (30 mph)? OR: * If neither a voltmeter nor frequency counter is available, vehicle speed control may be used as a good indicator. If it works normally, then the speedometer module is at least receiving a speed input signal and the wiring and sensor & tone ring can be assumed to be good.
This is tuff to do; suggest using str8 pins to back probe the connector

Read More @ http://fullsizebronco.com/forum/showthread.php?t=201477

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Try a Self Test for Diagnostic Trouble Codes (DTC)s by my pal, BroncoJoe19

The engine temperature must be greater than 50° F for the Key On Engine Off (KOEO) Self-Test and greater than 180° F for the Key On Engine Running (KOER) Self-Test.
Run it around to heat the engine up and shift thru all gears incl Reverse. Then turn off all accessories/lights, etc.

Make sure A/C is off and transmission is in Park (automatic) or in Neutral for a Manual & release clutch.

Do Key On Engine Off (KOEO) portion first.

And Post them here according to:
KOEO
&
KOER




Odometer & Keyless Entry Inoperative; Fuse 8 Overload, Possible Short In Circuit 54 TSB 95-14-11 for 94-95 Bronco & F Series; also affected Inoperative Courtesy, Map, Engine & Glove Compartment, Dome, Vanity, & Cargo Lamps & Inoperative Power Mirrors
Splice 216 to Ground G200, Instrument Cluster ground is inside passenger side kick panel
 

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Discussion Starter #4
Speed input signal test. Do I do this to the connector that connects to the back of the psom? Or a connector under the hood? I read about this test and I believe it's a good way to see if tone ring and VSS is good. Thanks for all your help. I will be home soon and will begin testing the wiring and cleaning connectors.
 

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Would the odometer still show something in the little digital readout? Or would it be completely blank like mine is? Mine lights up but had no numbers. And the rest button does nothing when I turn the key over while holding the reset.
 

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yo,
Yes @ back of PSOM is preferable;
vehicle speed control may be used as a good indicator. If it works normally, then the speedometer module is at least receiving a speed input signal and the wiring and sensor & tone ring can be assumed to be good.
This is tuff to do; suggest using str8 pins to back probe the connector


Read in this referenced Link about the 4WABS Module failure (microprocessors burn out)
http://fullsizebronco.com/forum/showthread.php?t=201477
see; My 96's same symptoms were erratic until the 4WABS Module's microprocessors finally burnt-out. I had one go bad and 2 yard Modules were also bad; so I jumpered the Module out as Steve & Turbo Ghost describes below.

To bypass the 4WABS module @ it's harness's connector & feed the ABS signal directly to the PSOM,
Disconnect module (under coolant recovery /ws washer tank) & in connector, jumper LG/Bk to LG/Y, and R/Pk to O/LB..."
Source: by Steve83 (Steve, That dirty old truck) at
Report this image

Pin numbers are shown in the wiring diagram

or with a pic of the connector and jumpers; Continuity Test Through 4WABS Module Connector in 93-96; "...jumper 14 (CKT 530, LG/Y) to 21 (CKT 519 (LG/BK) & 39 (CKT 491 (O/LB) to 22 (CKT 523, R/PK)...";

Source: by Turbo Ghost at http://fullsizebronco.com/forum/showthread.php?t=141328

more stuff in the Link
Any slight dents, chips, etc., in either the exciter ring or VSS will create needle waver. Measure air gap between the VSS and exciter ring. It should be 0.38-0.51mm (0.015-0.020"). Check exciter ring runout per the same ring gear backface runout procedure of the appropriate model 1996 Powertrain/Drivetrain Service Manual, Section 05-00. Make sure the exciter ring is mounted correctly to the ring gear. If runout is more than 0.1mm (0.004"), perform the differential runout check per the procedure in the appropriate model 1996 Powertrain/Drivetrain Service Manual, Section 05-02A or 05-02D, to find cause and repair as needed

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Tone Ring Inspection; "Take off the rear diff cover. Check the Ring Tone gear. It is located on the left hand side of the ring gear. Look to see if any of the teeth have been notched (from debris floating around in the diff.) Usually a spider gear. If the ring tone gear has been notched, it will need to be replaced to fix your speedo reading. Jack it up and rotate the tires to look for the teeth to be notched/broken/bent..."
Source: by Bighibbi at FSB

I lost the Trip Odometer as well
 

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Discussion Starter #7
4WABS

I did the jumper test on the 4WABS, and it had no effect on the harsh shifting and no speedo, or odometer. So I am pretty sure the PSOM is bad. Its really cold outside. Weather is supposed to be better tomorrow so I will take the instrument cluster out and put the tester on the plug like you suggested. Odometer is still blank. Doesnt show anything. No letters or numbers. I tried the reset button while turning key on, nothing.. Do you have a pic of the plug that I am supposed to test for the signal from the VSS? Another forum sent a pic of a RABS next to the EEC test plug but my truck has a RED ABS plug instead of a RABS. And it looks different.
 

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yo,
See Steve's PSOM page @ http://www.supermotors.net/registry/2742/69150

Also, is your AMBER ABS (light orange to some with vision issues) Light on while driving? if so;
4WABS Self Test & Test Connector Diagram, Component Locations, DTCs, 93-96; USE THIS PROCESS! "...The 4WABS TEST Connector is red; located at the left-hand side (driver's side) of the engine compartment and marked ANTI-LOCK TEST; Light Flash Technique 1. Note: If 12V test light is not available, the amber ABS warning light also flashes during this test. Locate test connector in the engine compartment and install 12V test light between Pins C and E. 2. With the ignition off, jumper Pin E to B. 3. Turn key to RUN position. 4. Remove jumper between Pins E and B after 5 seconds. 5. Count light flashes of test light or amber ABS warning light..." read more;
Source: by Steve83 (Steve, That dirty old truck) at http://www.supermotors.net/registry/media/255501_1

Maybe we''ll see 33 Rear Axle Speed Sensor Diagnosis
Possible Source(s):
� Poor connection at vehicle speed sensor.
� Terminal damage or backout in anti-lock brake electronic control module connector Pins 21 or 22.
� Terminal damage or backout in two-pin sensor connector.
� Open or shorted vehicle speed sensor coil.
� Open or shorted Circuit 518 (LG/R) or 519 (LG/BK).
� Improper vehicle speed sensor cable routing leading to above.
� Defective vehicle speed sensor electrical test circuit in anti-lock brake electronic control module. Note: some vehicles were built using Circuit 523 (R/PK) in place of 518 (LG/R).

77 Rear Axle Speed Sensor Diagnosis (Dynamic)
Possible Source(s):
� Damaged/missing indicator ring teeth or missing indicator ring.
� Air gap too small or too large.
� Excessive axle vibration.
� Weak rear axle sensor.
� Loose rear axle sensor.
� Disturbances caused by ignition or radio frequency interference.
� Defective trigger circuit in anti-lock brake electronic control module.
� Intermittent short or open in Circuit 518 (LG/R) or 519 (LG/BK). Note: Some vehicles were built using Circuit 523 (R/PK) in place of 518 (LG/R).

ABS and Speedometer Are Not Functioning Properly
Possible Source(s):
� No signal to anti-lock brake electronic control module from vehicle speed sensor.
� No signal to speedometer from anti-lock brake electronic control module.
� Defective vehicle speed sensor.



For pin-point testing of a 4WABS Code(s) see http://fullsizebronco.com/forum/showthread.php?t=192557

lieu of the obsolete Ford Rotunda pin-out box (avail. on e bay, etc. but often it does Not include the overlays or cables), you can go to the connector (cited in test) pins instead
 

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Discussion Starter #9
No, the ABS light is not on while driving. Thanks for the link to test the PSOM. Just what I needed. I will give it a shot tomorrow.
 

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Would the odometer still show something in the little digital readout? Or would it be completely blank like mine is? Mine lights up but had no numbers. And the rest button does nothing when I turn the key over while holding the reset.
Then check your fuses. If you don't have any numbers showing, then the problem lies with the PSOM itself. Sounds like an electrical connection, blown fuse or it just died.
 

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Then check your fuses. If you don't have any numbers showing, then the problem lies with the PSOM itself. Sounds like an electrical connection, blown fuse or it just died.
Exactly what I was thinking. The backlighting comes on when I turn on headlights, but other than that, no letters or numbers. Nothing happens when I hit the reset while turning key over. Wish me luck tomorrow! Hope to find something when I dismantle the PSOM. :)
 

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to,
Yes ck Fuses;

Check Fuses 8 & 18 in Cab fuse block (lower left of dash by driver's left knee)
If no 12 v on Supply Side of each; look in Power Distribution Box (PDB) Located under the hood on the drivers side fender well, on driver's side of the air cleaner housing
and check MAXI FUSES J & S
this is in my referenced post @ http://fullsizebronco.com/forum/showthread.php?t=201477
Fuse Block Diagram in a 95 Bronco http://www.revbase.com/BBBMotor/Wd/DownloadPdf?id=46678

PDB Diagram in a 95 @ http://www.revbase.com/BBBMotor/Wd/DownloadPdf?id=46677

see if a previous owner or shop rigged the fuses with taps or other crap.
 

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Has anyone looked at the PIC? Do you think this board can be saved?
yo,
I can't guess on its operational condition due to Bad Internet connection (Heavy Rain) & am guessing that is mold or mildew on the board?
you could try to clean it. here is some info; ",,,use a q-tip with rubbing alcohol(70% or higher), and only use a toothbrush if there is a pretty heavy encrustation...and for that, I use an "Extra Soft" brush VERY gently.
This, of course, is assuming that compressed air won't do the job.,,," by Kaptain Skitzo

See this pic & compare;

by Steve83


Some tips;
K3 CHECK INSTRUMENT CLUSTER PRINTED CIRCUIT
•Inspect instrument cluster printed circuit for damage, poor connections or open circuits.
Is instrument cluster printed circuit open or damaged? Yes
REPLACE instrument cluster.
Same for the PSOM.

CHECK FOR CORROSION/POOR CONNECTIONS
•Visually inspect the wiring harness connections for corrosion and poor connections.
Is there corrosion? Are there poor connections? Yes
REPAIR as required.


ERROR Message; Does the word ERROR appear on the odometer display? YES - REPLACE instrument cluster. NOTE: ERROR 3 means conversion constant must be programmed. See Pinpoint Test F; Refer to Speedometer Calibration Tolerance Specifications table under Specifications in this section. Be sure to check the odometer calibration. If both the odometer and speedometer are incorrect in the same direction, it is usually a sign that the conversion constant, tire size, or speed sensor ring are different than programmed. A speedometer inaccurate with an accurate odometer is usually a problem with the speedometer module itself..." READ MORE
Source: by Ford http://www.thedieselstop.com/faq/9497faq/maint/stj/stjd1017.htm

"...The instrument cluster requires special handling to avoid damaging internal components. The cluster MUST be kept FACE UP or in the in-vehicle position. Leaving the cluster face down may result in a loss of dampening fluid used in the gauges. The lost fluid could stain the cluster face or result in excessive pointer waver..."
Source: by Ford via miesk5 at FSB

Adding Mileage to Odometer; "If the junkyard odo is LOWER than yours, you can "reprogram" it yourself using a free program called GoldWave, your computer sound card, & your stereo to generate a square wave signal to just add miles. I ran the sound card headphone signal out to a big Kenwood home theater receiver, then the speaker outs from THAT to the PSOM speed signal inputs. I turned the volume ALL the way down, then used GoldWave to generate the square wave at the freq. I wanted (~2KHz IIRC), and slowly increased the receiver's volume until the needle came up. Then I just let it run - no smoke got out, and the guy who bought it said it worked fine. That was several years ago (check the UL date on that photo) and he hasn't come back complaining about it, or asking for another PSOM, so I can only guess it's still working...Alternatively, you might get a junkyard ABS sensor & place it near a metal fan blade (a squirrel-cage blower would probably be best), wire it up to your PSOM, and let it count that for a few days"
Source: by Steve83 (Steve, That dirty old truck) at FSB
http://www.supermotors.net/registry/2742/69150


Failure Due to a Bad Solder Joint; "...Worse case in terms of $ is the PSOM is in the instrument cluster will need repair/replacement...I saw a fix in f150online by someone who worked on a 97 PSOM; the problem turned out to be a bad solder joint; author said this is the cause of late model (95 and up) Bronco and 97+ F series PSOM failures..."
Source: by miesk5 at http://www.fullsizebronco.com/forum/showthread.php?t=8218&highlight=keyless+connector

For a YARD SEARCH on-line, I use;
http://api.viglink.com/api/click?format=go&jsonp=vglnk_14221055789097&key=6ed47b392b9edfe394b9e89b72717104&libId=6e7031f2-2b5e-49b5-927f-3e44d617df3a&loc=http://www.fullsizebronco.com/forum/showthread.php?p=4688130&posted=1#post4688130&v=1&out=http://www.hollanderparts.com/&title=What did you do to your bronco today? - Page 427 - FSB Forums&txt=http://www.hollanderparts.com/
Select All Parts
year, etc, then FORD TRUCK

--
or
http://www.copartfinder.com/finder/searchMake.do
Has Vehicle Pics!

http://www.picknpull.com
This is a Company name w/yard locations in various states
 
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