(from Tommy Tubosaurus)
Hmmmm... . Good question! I don't see why you couldn't run wiring directly from the computer to the connector behind the fuse panel. A service manual would give you the connections. If you did it that way, you wouldn't even need the upper harness; you could solder directly to the pins on the computer connector.
The lower harness runs up the A-pillar from the fuse panel beside the instrument cluster and supplies power and data to the computer and the auto-dimming mirror, if you have one. The upper harness is just a short little guy that appears to adapt the computer's connector to something more 'automotive' in appearance.
I guess the only reason to use the factory harnesses is to keep the truck..... well..... factory.
I hope I've answered your questions to your satisfaction. If not, let me know how I can help.
By the way, I haven't installed a computer yet as they're still bloody expensive here in Kanada. I never thought one would show up in the TDR classifieds! I'm giving some consideration to upgrading to a 2003, and the computer won't really affect the trade-in value.
TommyTurbosaurus)
Alrighty I climbed into the dash during lunch, the three wires for the lights on the overhead console, go into their own plug on the bottom of the fuse box, I saw the lower harness you describe but it looks like I won't need it. Anyway I ordered the upper
05013608AA, about 33. 00 and the Ambient Temperature Sensor.
20. 00
I assume from your earlier email that no wiring harness is needed for the ATS (Ambient Temperature Sensor).
I'll keep you informed.
Woody