speedometer problem
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Freshman User
Joined: Aug 2007
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speedometer problem
What are the most likely probnlems witha speedometer that just quit working? I have a 94 F150 and all the other gauges work fine, the speedometer just stopped working today. Thanks in advance for any help.
Hotshot
Joined: Jul 2003
Posts: 12,177
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From: Newport, WA
VSS in the rear end- it's the only sensor back there, 2 wires, bolted right to the top of the differential. If not that, open the rear diff and check the tone ring- it's what sends the signal to the VSS. Next culprit is wiring between the VSS and the PSOM (behind the speedo). Last thing to check is the PSOM. If its your PSOM, you'll want to junkyard a used cluster, just be aware that your truck will show whatever mileage the donor rig had because the PSOM stores mileage info.
Junior User
Joined: Mar 2003
Posts: 67
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I too have no speedometer. It jumps when I deccelerate. I have changed the VSS (ABS sensor) in the top of the rear differential. What is the PSOM? I am thinking the tone ring since the speedo works while decceleration?
Elder User
Joined: Nov 2005
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dehamma
Your 89 has a mechanical speedometer, it is much different than the 94 that was being discussed.
You need to pull the speedometer cable at the tranny. I would slide the innner cable out of the sheath to see if it is well greased, or possibly broken. If it is ok, grease it well and reinsert it. Then chuck the end up in a drill and spin it while someone else watches the speedometer. If the needle still doesn't turn, the gauge is bad. If it works fine, the gear driving the cable in the tranny is bad.
Good Luck Frank
Your 89 has a mechanical speedometer, it is much different than the 94 that was being discussed.
You need to pull the speedometer cable at the tranny. I would slide the innner cable out of the sheath to see if it is well greased, or possibly broken. If it is ok, grease it well and reinsert it. Then chuck the end up in a drill and spin it while someone else watches the speedometer. If the needle still doesn't turn, the gauge is bad. If it works fine, the gear driving the cable in the tranny is bad.
Good Luck Frank
Junior User
Joined: Feb 2008
Posts: 58
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From: Fairfield oh
I've got an 87 f-150, speedometer was making a light ticking noise. Was running fine until all of a sudden would not shift into 3rd gear. Did transmission filter change, Still no 3rd gear. Replaced speed sensor where cable goes into transmission. Now runs great with no ticking. I think the ticking sound was the sensor going bad.
