fury

I researched quite a bit, and found many people saying that you can tap into your tach signal by tapping into a screw which is at the back of your gauge cluster. Some people said that on the RD1, that screw is labeled "T/C", and that on the RD2, it's labeled "ta sig". I have a 99, but the only code printed on that circuit board that even comes close to Tachometer, is "T/M Unit". Can anyone confirm that this is the tachometer signal?

I tapped into it anyway, and took my multimeter and tried to confirm that it was. Here's what I did. I set my multimeter to ACV, and put it to 200 (I don't have a 20V setting, only 200V and 500V). Anyway, with the car on, I connected black (-) to ground and positive (red) to a wire which was tapped into that screw. The multimeter read, 17.1. I tried to rev the engine but the value only went to 17.2, or somthing. Even if I tried to rev even more, it wouldn't go above 17.2. I read that it was supposed to read btwn 1 and 6V and that as you rev, it's supposed to increase.

Ericy321

Hey man, just checked and thats it. I looked at my RD2 cluster which said ta sig. And that same place on my rd1 had the label of t/m unit slightly above it. So I would say thats it. You should check it with the meter on DC voltage, not AC voltage and I think you will see its correct.

fury

Thanks Ericy! I'm gonna try it on DC. It makes me feel better to know that "T/M Unit" was the right one. A lot of people were saying that on the rd1 it was supposed to say, "T/C". Thanks again, man.

DTN

Yeah, that would have to be it. I'm looking at mine, one is power, one is ground. Mine is labeled TA sig. That's the only wire that leaves the circuit board. It would take Power Ground and Signal. Being that is the only possible signal wire going to the tachometer, it would have to be it. I thought the Tach signal was a pulsed DC output, not a fluctuating voltage though.

Ericy321

Ehh, it doesnt matter. And I believe it is regular DC. Thats the one though. Hook up the tach there and watch it work. What tach you putting in?

Alex01tib

Yah if your putting in a big tach, i'd suggest you dont.

But if your looking to tap the RPM signal for a piggyback i'd say use the crankshaft position sensor, its been said to be more reliable. Thats where i tapped mine...

DTN

^^ isn't that just the other end of the wire?

Alex01tib

Nah the crankshaft signal goes from the CKP to the ECU then the ecu sends out the RPM signal to the tach through the engine speed output pin to the tach

DTN

^^ I knew it had to origonate from there. It must be amplified by the ECU, which can cause some signal distortion. I couldn't find the direct path anywhere in the schematics. Everything seems to end at the connector on the cluster or the ECU.

fury

Using DC showed 7.8V. I was using AC 'cause everyone says that the tach signal is AC.

Actually, I'm using the tach signal for a remote starter/alarm. I can't get the damn remote starter to work, yet. Every time I hit the RS button, I get "tach" error message. I haven't connected ACC nor door triggers, yet, but I don't think those should interfere.