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Discussion Starter #1
Like the title says... What type of signal is sent to the speedo? How does it register it and translate it into the needle moving? I assume that whatever type it is it either gets weaker or stronger meaning that the gauge would read faster or slower. I have a little project in mind and need help with figuring this out and how I could reproduce this signal and control it.
 

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This is how they used to work, with a VSS signal. But the JK has a CANBUS system and if it's anything like my Xterra, there is no dedicated signal and it's sent through the computer. So it's way more complicated than it used to be...but search around for VSS signal that people need for aftermarket navigation and the info should be in there.
 

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i belive its data also know as magic, im pretty sure theres a vss signal at the radio harness though, but you might need a aftermarket radio harness to use it
 

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Discussion Starter #4
I basically want to intercept the wire that feeds the speedo and take what I need from there. If you remove the cluster in a JK and start the enigne the wipers and I think blinkers will start running. Plug it back and and they stop. I then started removing one wire at a time from the harness plug that plugs into the cluster to track down exactly which one was feeding the signal. It is one of a couple wires as once I remove either of them it starts the wipers/blinkers routine again and the speedo/odometer stops working. I need to know what type of signal this is, how to read it, and how to reproduce it. My goal would be to even while sitting still be able to turn a twist knob and adjust the speedo from 0 to 100mph. Basically sending a false signal to the speedo to manipluate the speed it is showing.
 

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The cluster is like a small computer on a network. There are a few functions of the dash that are not transmitted over the network but speed is not one of them.

To really do this you need to remove all the abs speed sensors and substitute one of those signals. The ecu will use any of the four speed signal channels that has an input.

Keep in mind what this will do to transmission control, engine control, abs and ESP.

The ecu can also estimate miles driven if the signals it sees don't all make sense. This will cause some friction at the dealer if the ecu is scanned.

Still having a hard time figuring out what you are after....
 

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. My goal would be to even while sitting still be able to turn a twist knob and adjust the speedo from 0 to 100mph. Basically sending a false signal to the speedo to manipluate the speed it is showing.
why would you want to display fake speed?
 

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Discussion Starter #9
I am looking to quickly change the display to correct for tire/wheel changes. Just a project I am interested in. I am also very interested in how it works since it is a different system that most out there.
 
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