1990 K1500 SPEEDOMETER INOP

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Seosamh

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Hello All.
1. I have the whole wire harness from the transfer case to firewall took all the looms off and repaired four wires for the transmission connector "4L60 Non electric".
2. Replaced the VSS.
3. Replaced the speedometer.
4. Tested the CC module according to the shop manual with an ohm meter, no incorrect voltages or incorrect open circuits.
Still no Speedometer. My next step is to identify the wire from the VSS to the ECM. Its driving me crazy so if anyone has any other suggestion it would be appreciated.
Also its an unlikely fault but I was going to inspect the tone wheel on the output shaft for its clearance to the VSS.
Today wile testing wires for continuity behind the glovebox, see image. No part number on it just has: PED. Looks like a resistor on it. Anyone ever see this?
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Schurkey

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If your '90 is like my '88, the VSS drives the instrument cluster, not the ECM.

The instrument cluster modifies the VSS signal for use by the speedo, odometer, cruise, ABS, and ECM/TCC.

When my speedo went intermittent, I'd lose the odometer, cruise, ABS, torque converter clutch, and light-up the MIL.

Replaced sensor--no change. Replaced speedo--no change. Replaced instrument cluster and everything worked consistently.
 
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