jbwilli
Active Member
- Joined
- February 14, 2012
- Messages
- 61
- Reaction score
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- City, State
- marietta ga
- Year, Model & Trim Level
- 1997 SPORT 2009 EXP EB
I made this post on another forum years ago! I am posting it again on this forum to assist anyone who has or had the same issue AND to help qualify me to join the Elite Explores via helping others! And get rid of these pop-up ads! I have received many emails from many others over the years on this post and ALL responded it solved their problem! Here it is:
I See All The Post On Erratic And Or Inop Speedometers On Explorers. I Have Been Chasing The Same Problem For A Year Now, And Have Read And Learned A Lot From All Of You Posters On The Subject. I Have Finally Found My Problem, And Wanted To Share With You What I Learned On How To Trouble Shoot This Annoying Problem. This Is For The Non-speedometer Cable System..mine Is A 1997 Sport 4x4.
To Troubleshoot Anything, You Need To Know How It Works. This System Is Basically Very Simple. This System Sends A Voltage To The Speed Sensor, That Opens And Closes Once Per Rev, Via Plastic Gears. This Signal Is Sent To The Instrument Cluster Solid State Unit, That Uses This Signal To Drive The Speedometer Needle. That's It!
So, You Have To Have Voltage To The Speed Sensor, The Speed Sensor Must Turn Via The Plastic Gears In The Transfer Case, The Speed Sensor Must Interrupt The Voltage Once Per Rev, And Most Important, The Grey/black Wire That Carries This Signal Must Have Continuity From The Sensor, To The Terminal Plug At Back Of The Cluster And From That Printed Circuit Connection Point, To The Solid State Unit That Drives The Needle!
This Is What I Learned:
Mine Started After I Had To Remove Instrument Cluster To Replace A Bulb.
There Is A Spiral Plastic Gear Inside The Transfer Case. You Can See It In The Hole, When You Remove The Speed Sensor. Ensure That Gear Is Not Damaged (very Rarily Is). The Speed Sensor Also Has A Plastic Gear On It. Ensure It Is Undamaged (very Rarely Is).
The Speed Spensor Can Be Checked With A Meter. Take It Out And Hook Up To The 2 Terminals. Turn It By Hand. Continuity Should Open And Close Once Per Rev.
You Can Also Check The Wires Coming To It With A Meter. The Grey/black Wire Goes To The Terminal Plug On The Back Of The Instrument Cluster And With Key Off, Check With Ohmeter To See If It Is Grounded. Place One Lead On This Wire The Other To Frame Or Good Ground. It Should Read Open, Not Grounded. Now Turn The Key To On And Check For Voltage...mine Read About .5 Volts. Now Turn Key Off And Check For Continuity Of The Pink/orange Wire. Connect One Lead To It And The Other To Frame Or Good Ground. It Should Read Grouded.
Now Hook Up The Terminal Back Onto The Speed Sensor, But Leave The Speed Sensor Hanging Out, Not Installed. Remove The Instrument Cluster. There Are 3 Terminal Gangs That Plug Into The Back Of The Cluster. The One At The Top Middle Area Is Where You Will Find The Grey/black Wire That Comes From The Speed Sensor.
It Is On The Bottom Row, Far Right End, As You Look Into The Plug At The Cluster. Now, Backprobe The Pink/orange Wire At The Speed Sensor Connector With One Lead, And Connect Other Lead To Grey/black Wire In The Terminal Plug At The Instrument Cluster.
Hand Turn The Sensor. You Must Get A Once Per Rev Pulse.
Now Check The Continuity Of The Back Of The Instrument Cluster From The Printed Circuit Copper Strip Where The Grey/black Wire Would Make Contact, To That Litte 1/4 Inch Square Metal Piece, That Is Just An Inch Or 2 To The Left,as You Face The Back Of The Cluster. You Will See 3 Of These. You Want To The One To The Far Left, As You Face The Back. This Is The Solid State Terminal Device, That Goes Eventually To The Speedometer Needle. There Must Be Continuity Between These 2 Points. While Checking, Run Your Finger Tip Across The Plastic Printed Circuit Board In This Area. Continuity Must Remain Constant.
Mine Did Not. The Path From Where The Black/grey Wire Attached To The Circuit Board Has A Discontinuity When Flexed. This Explained Why My Speedometer Worked Erratically. When Mine Dropped Out, I Could Hit The Dash Above Speedometer, And Usaully It Would Come Back On Line! The Only Fix, Is To Replace The Cluster, Or Solder A Tiny Gage Wire Between These 2 Points To Make The Connection Path 100% Reliable Again!
This Is Why I Think So Many Of Us Have That Erratic Problem. Temperatures, Age And Vibrations, 'flex' That Plastic Where The Printed Circuit Is Chemically Attached. I Feel Pretty Sure, I Must Have Disturbed That Area, When I Pulled The Cluster To Replace That Bulb A Year Ago.
Good Luck, And I Hope This Helps.
Final Note: You Can Plug All 3 Connectors To The Back Of The Cluster Before You Re-install The Cluster, Then Turn The Key On And Hand Turn The Un-installed Speed Sensor By Hand (turn It Pretty Fast!), And If All Is Well, You Will See The Speedometer Needle Go Up To About 20 Mph..do This, As A Final Check, Before You Put It All Back Togeter Again. You May Want To Start Here First, And Work Backwards From My Trouble-shooting Above, To Find Your Source Of The Problem.
I See All The Post On Erratic And Or Inop Speedometers On Explorers. I Have Been Chasing The Same Problem For A Year Now, And Have Read And Learned A Lot From All Of You Posters On The Subject. I Have Finally Found My Problem, And Wanted To Share With You What I Learned On How To Trouble Shoot This Annoying Problem. This Is For The Non-speedometer Cable System..mine Is A 1997 Sport 4x4.
To Troubleshoot Anything, You Need To Know How It Works. This System Is Basically Very Simple. This System Sends A Voltage To The Speed Sensor, That Opens And Closes Once Per Rev, Via Plastic Gears. This Signal Is Sent To The Instrument Cluster Solid State Unit, That Uses This Signal To Drive The Speedometer Needle. That's It!
So, You Have To Have Voltage To The Speed Sensor, The Speed Sensor Must Turn Via The Plastic Gears In The Transfer Case, The Speed Sensor Must Interrupt The Voltage Once Per Rev, And Most Important, The Grey/black Wire That Carries This Signal Must Have Continuity From The Sensor, To The Terminal Plug At Back Of The Cluster And From That Printed Circuit Connection Point, To The Solid State Unit That Drives The Needle!
This Is What I Learned:
Mine Started After I Had To Remove Instrument Cluster To Replace A Bulb.
There Is A Spiral Plastic Gear Inside The Transfer Case. You Can See It In The Hole, When You Remove The Speed Sensor. Ensure That Gear Is Not Damaged (very Rarily Is). The Speed Sensor Also Has A Plastic Gear On It. Ensure It Is Undamaged (very Rarely Is).
The Speed Spensor Can Be Checked With A Meter. Take It Out And Hook Up To The 2 Terminals. Turn It By Hand. Continuity Should Open And Close Once Per Rev.
You Can Also Check The Wires Coming To It With A Meter. The Grey/black Wire Goes To The Terminal Plug On The Back Of The Instrument Cluster And With Key Off, Check With Ohmeter To See If It Is Grounded. Place One Lead On This Wire The Other To Frame Or Good Ground. It Should Read Open, Not Grounded. Now Turn The Key To On And Check For Voltage...mine Read About .5 Volts. Now Turn Key Off And Check For Continuity Of The Pink/orange Wire. Connect One Lead To It And The Other To Frame Or Good Ground. It Should Read Grouded.
Now Hook Up The Terminal Back Onto The Speed Sensor, But Leave The Speed Sensor Hanging Out, Not Installed. Remove The Instrument Cluster. There Are 3 Terminal Gangs That Plug Into The Back Of The Cluster. The One At The Top Middle Area Is Where You Will Find The Grey/black Wire That Comes From The Speed Sensor.
It Is On The Bottom Row, Far Right End, As You Look Into The Plug At The Cluster. Now, Backprobe The Pink/orange Wire At The Speed Sensor Connector With One Lead, And Connect Other Lead To Grey/black Wire In The Terminal Plug At The Instrument Cluster.
Hand Turn The Sensor. You Must Get A Once Per Rev Pulse.
Now Check The Continuity Of The Back Of The Instrument Cluster From The Printed Circuit Copper Strip Where The Grey/black Wire Would Make Contact, To That Litte 1/4 Inch Square Metal Piece, That Is Just An Inch Or 2 To The Left,as You Face The Back Of The Cluster. You Will See 3 Of These. You Want To The One To The Far Left, As You Face The Back. This Is The Solid State Terminal Device, That Goes Eventually To The Speedometer Needle. There Must Be Continuity Between These 2 Points. While Checking, Run Your Finger Tip Across The Plastic Printed Circuit Board In This Area. Continuity Must Remain Constant.
Mine Did Not. The Path From Where The Black/grey Wire Attached To The Circuit Board Has A Discontinuity When Flexed. This Explained Why My Speedometer Worked Erratically. When Mine Dropped Out, I Could Hit The Dash Above Speedometer, And Usaully It Would Come Back On Line! The Only Fix, Is To Replace The Cluster, Or Solder A Tiny Gage Wire Between These 2 Points To Make The Connection Path 100% Reliable Again!
This Is Why I Think So Many Of Us Have That Erratic Problem. Temperatures, Age And Vibrations, 'flex' That Plastic Where The Printed Circuit Is Chemically Attached. I Feel Pretty Sure, I Must Have Disturbed That Area, When I Pulled The Cluster To Replace That Bulb A Year Ago.
Good Luck, And I Hope This Helps.
Final Note: You Can Plug All 3 Connectors To The Back Of The Cluster Before You Re-install The Cluster, Then Turn The Key On And Hand Turn The Un-installed Speed Sensor By Hand (turn It Pretty Fast!), And If All Is Well, You Will See The Speedometer Needle Go Up To About 20 Mph..do This, As A Final Check, Before You Put It All Back Togeter Again. You May Want To Start Here First, And Work Backwards From My Trouble-shooting Above, To Find Your Source Of The Problem.
