Good evening all,

I have a 1986 SDL with 280,000 miles? I have had problems with the speedo, odometer, and clock not working. I had the original transmission overhauled. Before the overhaul and afterwards the mentioned items have not worked. I've had a mechanic check it out, and he's mentioned there is very little pulse feeding into the speedo. I have even tried switching the entire unit out with a unit I got at tbe bone yard. The switch didn'tt make any difference.

Does anyone have access to the wiring diagram for the speedo? Any suggestions of what to try next? Any and all assistance is appreciated.

Thanks in advance for your assistance.

Ron

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Hi Ron,

The speedo is fed a signal that comes out of the tail section of the transmission. This wire travels up into the cabin and into a connector on the left side of the transmission tunnel. A wire exits this connector then goes up into instrument cluster via a 6-pin connector on the back of the speedometer.

What I would do is make sure you have power and ground at the 6-pin connector that plugs into the speedometer unit. This provides power to the speedo/odo and ground to the entire cluster.

Do any of the other gauges work?

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Good evening and thanks for the reply. I will look into it and get back to you soon. I appreciate your advice and diagram.

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