MS3 pro no dash tach NA chassis
#1
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MS3 pro no dash tach NA chassis
Ok I'm not sure what I'm doing wrong. I directly wired the tach output to the dash cluster but I don't get any tach output besides a quick bounce every once and a while. The MS3P supposedly directly outputs a 12v square wave so I didn't add any pull up or pull down resistors, that's the right thing to do right? What am I missing?
#4
You're thinking the voltage is being sourced through the transistor - which most of the time in automotive it's not. It's almost always switched to ground. Which is why you need the pullup resistor. Without the pullup, there's float voltage and then ground which isn't enough to trigger the tach reading a change.
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"4.9 Tach output The tach output supplies a 0 to 12 volt square wave that is compatible with many factory tachometers and nearly all aftermarket units. Just wire its output to the tach signal wire."
That's what the MS3P manual says.
That's what the MS3P manual says.