On board computer hack - how long is the wiring harness?

[The Sandman]

Originally Posted by ddruker

I finished this project up today and everything worked fine on the first try.

18 inches is plenty of length if you are making your own wiring harness rather than buying the premade Volkswagen wires specified in many of the guides.

I can confirm that the molex pins I listed above do work for both ends of your cable. They are a little bit wiggly when you place them inside the gray connector that connects to the cluster, but they do fit correctly with the male pins built into the cluster from an electrical perspective.

Now that I'm done I would say I am very modestly impressed with this hack. I guess it's state of the art for 2001. I suppose it's kind of nice to know the outside temperature and how many miles the box thinks it can go before empty, but overall it's a bit underwhelming now that I actually see it in action...

I am curious... I have a 2001 and understand that a stalk or rocker switch is required to be installed in order to even get the temperature reading.

These are essentially momentary switches though... once I attach a switch (and have the computer activated for OBC) and advance until the temp shows, can I then remove the switch? Will the car show temp then by default next time I start or do I have to use the switch to select it with each restart?
Dave

[rick3000]

Originally Posted by The Sandman

I am curious... I have a 2001 and understand that a stalk or rocker switch is required to be installed in order to even get the temperature reading.

The OBC is turned on by the dealer with a PIWIS, PST2, or you can do it yourself with a durametric. The switch does not activate the OBC features, and if the OBC is activated without a switch or stalk it will always default to the first "page" which is the exterior temp (EDIT - This is only for earlier cars, see JFP's response below). If you cycled to a different "page" the next time the battery was disconnected it would default back to the first page which is the temp display. A switch is only required if you want to cycle through the other "pages" including avg. MPG, miles to empty, avg. MPH. With 2 switches or the stalk you can also set the speed gong feature.

[JFP in PA]

Originally Posted by The Sandman

I am curious... I have a 2001 and understand that a stalk or rocker switch is required to be installed in order to even get the temperature reading.

These are essentially momentary switches though... once I attach a switch (and have the computer activated for OBC) and advance until the temp shows, can I then remove the switch? Will the car show temp then by default next time I start or do I have to use the switch to select it with each restart?
Dave

You are correct, on the 2001 just activation of the OBC system will not result in any display; there must be either a momentary switch attached or the fourth stalk, which is nothing more than a fancy momentary switch. If you remove the switch, the display will go dark. Once the switch is installed and system activated, the display will retain the last setting on restart of the vehicle.