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Discussion Starter #1
Hi everyone, I recently bought the gauge pack that could be installed on older foresters and Imprezas, the one that includes a compass, barometer, altimeter, and exterior temp. One of the wires (the single blue one) has to be tapped into the speed sensor wire under the steering column. It is easy to find information about where this is in a 98 Forester (manual transmission if it matters) , but I cannot find where the speed sensor wire is on my 2002 Forester. The plugs under the dash seem to be different in the 02 compared to the 98. If anyone has information or knows which wire I need to tap into, it’d be greatly appreciated!
 

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2003 EJ20K Forester
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The VSS (vehicle speed sensor, ground speed) is different between those generations. First gen forester used a 2-wire VR sensor which generated an AC voltage with amplitude/frequency proportional to speed (up to 20 volts!). Second gen used a 3-wire hall effect which generated a square, constant voltage wave. The instrument cluster in gen 1 translated the VR AC wave into a square wave for the ECU to interpret. Luckily, the speed sensors are interchangeable, so you can just swap in the one you need.
 

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Discussion Starter #3
@RyanT
Mine is still a first gen, wouldn’t it use the same sensor and wiring as the 98? First gen was 98-02. Mine is the facelift 1st gen though.
 

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Ah sorry, 2002 was the gen change year as far as I knew. You should have the same wiring then. I believe the speed sensor was red and white twisted pair, but if its not that I can't help you, sorry. I am surprised that your new cluster is only looking for 1 wire input on speed - that suggests it is wanting the digital input. If I were you I would make sure you have the right input for that blue wire just in case you fry it with the VR input.
 

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Discussion Starter #5
@RyanT thanks, I’ll try looking for that. If anyone else who has any clues could let me know it would help out a lot!

It says in an old installation manual that I’m looking for a blue 24 pin connector, and should tap into the green/black speed signal wire. I don’t think my car has the same blue 24 pin connector, and I don’t want to tap into the wrong wire.
 

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Ah green/black rings a bell. That should be the digital speed signal between the cluster and the ECU.
 

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Discussion Starter #7
@RyanT well after some more research, it seems that you were pretty much correct with your initial response, except that the change in sensors happened earlier than the 2nd gen from what I can tell. The 98 used the 2 wire VSS (85082AC002), while the 99+ used the 3 wire (85082AE000). So now the question is whether or not I can tap the blue speed wire into somewhere different and have it work properly. I found that somebody put the same gauge pack in a 2002 wrx, which also uses the 3 wire (85082AE000) VSS. (link to forum thread: https://forums.nasioc.com/forums/showthread.php?t=2742430) He said that he tapped into a green wire with a yellow stripe on position A1 on his ECU to make it work. It seems that the 3 wire VSS goes from the sensor to the ECU, and then to the cluster, so would tapping the speed sensor signal wire from the ECU to the cluster work?
 

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I thought the 2 wire VSS went to the cluster, which did the signal processing to make the digital signal for the ECU. I remember thinking it was an odd choice engineering wise. If you have the 3 wire VSS, then you should just be able to tap into that signal wherever is convenient - maybe at the ECU. If you have the 2 wire, you need to tap in between the cluster and the ECU - that might be the green/black you were talking about earlier.
 
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