1993 Toyota Pickup Speedometer Not Working

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MARS
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I have a 1993 Toyota pickup, 4x4, standard transmission, 93K miles. This truck has a speedometer sensor. I have located the sensor and want to determine if the sensor is bad or the wiring to the sensor is bad. The electrical connection to the sensor has 3 wires. Can I use a voltmeter to verify if the wiring is bad? What should I see when looking back to the speedometer cluster when I look at the 3 wires? How about looking into the sensor? Sorry I don't have the color of the 3 wires that go back to the speedometer cluster.

The odometer is not working as well as the speedometer not working. That is why I suspect I may have a wiring problem between the speedometer sensor and the console. I will be measuring resistance between the 3 wires that go from the sensor connection to the speedometer/odometer. I am not sure what to expect. I suspect I will see a resistance for the speedometer. The 3rd wire may go to a power source, I'm not sure. I was told the power sensor needs power but is not protected by a fuse. That is why I suspect a wiring problem. The speedometer went sporadic(ie bounced around for a few seconds) before it completely stopped working. Hope this helps.

Thanks
Apr 21, 2006 at 12:37 AM
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STRAILER
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Hey Mars,

I found the wiring diagram for you and none of the wiries head to the speedo they go into the the PCM.

A Toyota vehicle speed sensor is usually bullet proof. I have never seen a failure but I have seen a lot of speedometer failures. The VSS does a lot of other things besides a speedometer.

I have replaced dozens of instrument clusters on Toyota trucks and I have NEVER found a wiring problem or a bad vehicle speed sensor. The symptom of an occasional bounce is that of a bad cluster.

One truck I repaired had a corroded connector on the back of the cluster which I cleaned with a pencil eraser but never a bad wire or VSS. That was over a 20 year period.

Here is a diagram so you can do some testing please let me know what you find so it will help others

Best, Ken
Dec 22, 2016 at 6:40 AM

Suggested Repair

Suspect the instrument cluster rather than the vehicle speed sensor or wiring. The VSS signal goes to the PCM, and a bouncing then dead speedometer and odometer is typical of a failed cluster. Also inspect and clean the connector on the back of the cluster for corrosion before replacing the cluster.

Conversation Summary

The owner of a 1993 Toyota Pickup with a nonworking speedometer and odometer wanted to test the three-wire speed sensor and its wiring with a voltmeter and resistance checks. The expert said those wires go to the PCM, not the speedometer, and that Toyota speed sensors and wiring rarely fail. Based on many similar repairs, the bouncing-then-dead symptom points to a bad instrument cluster, with a corroded cluster connector as a less common cause that can be cleaned.

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