Tach wire, 2000 GMC Sierra?

Hello,

I am having some trouble locating the tach wire for a 2000 GMC Sierra Pick up truck, 8 liter engine.  All of the wire diagrams I have come across show the tach wire for the smaller engine models and the tach wire is different for every different one. 

I am installing a remote start on the vehicle and wonder if the fuel injector would be a better place to attach my tach imput on the remote start.  The fuel injectors appear to have three wires per injector as opposed to two wires.  Can anyone assist me with this?

Also, how do you use a multimeter to detect the correct tach wire if hunting for it?  I heard rumor that you can put the meter on AC and meter across ground & the suspected tach wire.  Anyone know for sure?

Thank you,

Porter392

-------------
porter392

"I heard rumor that you can put the meter on AC and meter across ground & the suspected tach wire. Anyone know for sure?
"


Correct, you should get a reading between 1-8 volts when you press on the gas pedal.





DIRECTWIRE™ WIRING INFORMATION - GMC / SIERRA / 2000 / Remote Start


12volts red   +   ignition harness
Starter yellow   +   ignition harness
Second Starter          
Ignition pink   +   ignition harness
Second Ignition white   +   ignition harness
Notes: To avoid the check engine light from coming on and possible damage to the automatic transmission, the second ignition in this vehicle MUST be powered when adding a remote start system.
Third Ignition          
Accessory orange   +   ignition harness
Second Accessory          
Keysense          
Power Lock lt. blue   +   brown plug at BCM
Notes: The BCM is located behind the drivers side of the dash. The plugs on the BCM face towards the rear of the vehicle. The parking lights are in pin A5 and the headlights are in pin A11.
Power Unlock white   +   brown plug at BCM
Notes: The BCM is located behind the drivers side of the dash. The plugs on the BCM face towards the rear of the vehicle. The parking lights are in pin A5 and the headlights are in pin A11.
Lock Motor gray      driver kick panel
Unlock Motor tan      driver kick panel
Parking Lights+ brown   +   lt. blue plug at BCM
Notes: The BCM is located behind the drivers side of the dash. The plugs on the BCM face towards the rear of the vehicle. The parking lights are in pin A5 and the headlights are in pin A11.
Parking Lights- white   -   lt. blue plug at BCM
Notes: The BCM is located behind the drivers side of the dash. The plugs on the BCM face towards the rear of the vehicle. The parking lights are in pin A5 and the headlights are in pin A11.
Hazards          
Turn Signal(L)          
Turn Signal(R)          
Reverse Light          
Door Trigger     -   BCM
Notes: Use tan for the drivers door located in pin B4 of the purple plug, and for the passenger door it will be a orange in pin B2 in the purple plug or dk.blue/white in pin B11 of the lt.blue plug, must diode isolate these wires.

The BCM is located behind the drivers side of the dash. The plugs on the BCM face towards the rear of the vehicle. The parking lights are in pin A5 and the headlights are in pin A11.
Dome Supervision          
Trunk/Hatch Pin          
Hood Pin          
Trunk/Hatch Release          
Power Sliding Door          
Factory Alarm Arm          
Factory Alarm Disarm lt. green   -   driver kick panel
Notes: Also found in the purple plug of the BCM.
Disarm No Unlock          
Tachometer white   ac   ECM
Notes: ECM is located near the battery, down low, between the fender and the fan under the black plastic cover. On the 4.3L, the tach wire is at pin 20 in the connector labeled red. On the 4.8L, 5.3L, and 6.0L, the tach wire is located at pin 10 in the red connector.
Wait to start dk. blue   -   instrument cluster
Notes: See DirectFax document 1090.
Brake Wire white   +   brake pedal switch
Parking Brake          
Horn Trigger black   -   brown plug at BCM
Notes: The BCM is located behind the drivers side of the dash. The plugs on the BCM face towards the rear of the vehicle. The parking lights are in pin A5 and the headlights are in pin A11.
Memory Seat 1          
Memory Seat 2          
Memory Seat 3          
Interface Module: Category:
Immobilizer Bypass Required:
Yes Type:
Passlock II
Part #: 556LW
Alternate Part1 #: 555LW
Alternate Part2 #: 555T
Notes:
Interface Module: Category:
Door Lock Interface Required:
No Type:
N/A
Part #: N/A
Notes:
Interface Module: Category:
Combo Interface Required:
Yes Type:
Data Bus
Part #: 457GW
Notes: Can use the 457GW to bypass the Passlock II, but it will not control the door locks on this model year.



      
This wiring information is being provided free of charge on an "as is" basis, without any representation or warranty. It is your responsibility to verify any circuit before interfacing with it using a digital multimeter.
Directed electronics, Inc. assumes no responsibility with regards to the accuracy or currency of this information. Proper installation in every case is and remains the responsibility of the installer. DEI assumes no liability or responsibility resulting from improper installation, even in reliance upon this information.





-------------
Be careful whose advice you buy, but be patient with those who supply it.