First off I'm swapping in a 1998 Vortec 454 and 4L80-E into my 1989 Silverado. I'm a bit confused about the TCC circuit. Here is a picture of the 1998 system.



It says that the TCC switch is opened when the brake pedal is pressed. It also says that that positive power is going to the PCM when the pedal isn't pressed.

Now here is a picture of the TCC switch for the 1989 system.



I'm thinking I can go with pin 420 on C371 and just solder another wire onto that and feed that to the 1998 PCM for the TCC switch signal. Does that sound right?