Torque Converter lockup wiring question.
 

I'm in the middle of my LQ4/4L80E swap, and my instructions that come with my standalone harness states in needs 12 volts input from my brake pedal.
does this mean 12v when the pedal is pressed in or 12v when my foot is off the pedal?
I know older cars (including my 87 Suburban) are 12v when your foot is off the pedal and goes to no volts when the peal is pressed in.

Re: Torque Converter lockup wiring question.
 

This is correct for all Gen III engines/PCM's.

Re: Torque Converter lockup wiring question.
 

It depends on which pcm you are using for early and late engines. Early ls1 style (24x) engines need 12 volts removed with brakes applued. Later e38 (58x) ecu need 12 volts applied with the brakes applied.

Re: Torque Converter lockup wiring question.
 

My motor/PCM is from a 2004. so I need zero volts when my foot is off the pedal, 12v when I'm pressing the brakes right?

Re: Torque Converter lockup wiring question.
 

Nope. Use a 4 pin gm switch from a 1990's s10. Two terminals for brake lights. Connect other terminal to switched ignition. Last terminal to purple tcc wire on pcm.

Re: Torque Converter lockup wiring question.
 

Technically on an '04 you'll need both. Pin 33 (purple wire) on the C1 connector (blue one) will need 12v when the pedal is not depressed, and pin 6 (light blue wire) on the TAC module plug needs 12v when the pedal is depressed. Your truck should already have the right brake pedal switch with the two sets of connections on it unless it didn't have factory cruise control, which I would think would be odd on a fairly loaded suburban.

Re: Torque Converter lockup wiring question.
 

is this the switch you are talking about?
My existing brake switch has connectors for cruise control that I won't need, could I use those, or would you recommend getting one from an S-10?

Re: Torque Converter lockup wiring question.
 

For what it's worth, this is what mine currently has.

Re: Torque Converter lockup wiring question.
 

That is the one you need. And just an FYI, since your truck has cruise already, it's only three more wires to hook up to make it work on the LQ4..... ;)

Re: Torque Converter lockup wiring question.
 

Do you have to use pin 6 (light blue wire) even when not using cruise control?