question re: tach signal out

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Dec 17, 2005 | 09:16 PM

TT_Vert

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From: Elgin, Illinois

question re: tach signal out

on C105 Plug
B PNK Hot with IGN 1 Relay Engaged (TCC Stop Lamp Switch/MAF/O2 20A)
D DK GRN PCM 37 Cruise Control Inhibit
F WHT PCM 13 Cruise Engaged Signal
G WHT PCM 10 Tach out to Brake Control Module
H PPL PCM 4 AIR Solenoid Relay Control

G is for the tach right? I dont have G wire in my C105, its got a rubber plug, I see no other white wires otehr then F which is for cruise signal, should I use this for speedo?

Thanks
dave

Dec 18, 2005 | 11:01 AM

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From: Gig Harbor, Wa

Based on your other posts I will assume this is a 99 Trans Am harness?

Pin 10 on C2 (the red PCM connector) is the tach signal.

Dec 18, 2005 | 12:12 PM

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From: Elgin, Illinois

99 firebird. What is C2? is that plug 220 or 230? Actually pin 10 in C1 is ENG. SPEED (TACH) OUTPUT SIGNAL. But there is a tach output signal that goes into car, either on C220 or C230 I thought

"C220 Pin K"
K DK GRN/WHT PCM 50 VSS Output

IS that sufficient for speedo ?
Dave

Dec 18, 2005 | 12:49 PM

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From: Gig Harbor, Wa

C2 is the big red connector on the PCM.

I think for the speedometer, you have to use the wires coming from the VSS, but it depends on your speedo.

Dec 18, 2005 | 03:10 PM

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I used they white wire you're referring to (C105 pin G) for a tach signal.

Keep in mind that you need to set your tach to 4cyl, or rescale in the PCM with HPT etc, to use this wire.

Dec 18, 2005 | 04:17 PM

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From: Elgin, Illinois

why would I not have a G pin in C105? It has the factory rubber block off on it.

Dave

Dec 18, 2005 | 04:54 PM

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From: Gig Harbor, Wa

Because the donor car did not have traction control. Pin G of C105 is the tach signal going to the Traction Control Module. The instrument cluster gets the tach signal from the serial data information coming from the PCM.