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Discussion Starter #1
Could anyone share how the tachometer is wired/ powered on an s4? I am trying to have my omex 600 ecu drive my tachometer but would like to have some direction before I go tearing into my dash.

The manual doesn't show how it is wired in and has the fuse diagram labels speedometer but no tachometer...

The old wiring harness does have two plugs that went from the engine bay back to the ecu. I have a hunch that these go back to the dash for the warning lights/ tach/ etc that isn't directly controlled by the ecu. Can someone clarify this?

Any help would be much appreciated, thanks!
 

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the rev counter gets the signal from the brown-white wire on the negative side of coil (from the ECU)
that goes to the G133b connector, seen here
rev counter dzm tacho wire connector2.jpg
which then goes to pin #1 of the black connector block "C" for the monopod instruments (under the dash near steering column) and then to the RED connector, also pin #1, connected directly to the back of the instrument pod and from there via the flexible circuit ribbon to the rev counter instrument itself.
monopod wiring loom.jpg

That's how I understand it at least!
 

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Discussion Starter #4
Dom, so if I'm reading that correctly, I simply need to wire my new tach driver into where the brown wire connected on the plug and can then ignore the green one that goes into the same plug? or is the green wire also needed for tach operation?

Thanks!
 

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Discussion Starter #5
I ended up just wiring into the white, It's all pretty accessible so if that doesn't work it shouldn't be a hard fix. I'll update once the engine is back in the car!
 
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