<div class='quotetop'>QUOTE(RedHeartbeat &#064; Jun 21 2006, 04&#58;56 PM) [snapback]55950[/snapback]</div>
The light blue/black wire has to be disconnected from the white box entirely, unplug the pin/terminal.

You might want to disconnect the purple/yellow wires from the original truck harness from speedo pickup sensor. You may only need that for anti-locks and cruise. I&#39;d isolate the white box from the input data until you find out for sure that is what is causing the speedo issue.
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Thanks,
Still no luck.
I cut the light blue/black wire at the vehicle speed sensor buffer box (the white one) and hooked the green/white wire from the pcm to it. No change.
Then I unplugged the entire white box and no change either.
So far I get the same result no matter which way I try.
Could it be that the pcm output is off that much? or is that a crazy thought.

Thanks again.
If anyone has other ideas, I&#39;ll be glad to try.

It&#39;s fun to drive, just be nice to know how fast I was going.LOL