Transmission Control Unit TB45-RE4 LS conversion

Hi I have just installed a LM7 5.3 Vortec engine in a 97 Y61 with a RE4 auto. (For those who don't know they are simply a cast block LS1 with slightly smaller pistons)
I know the Trans will go into failsafe (limp home) if I don't connect the TPS to the TCM somehow.
There are 2 plugs going the TB45 TPS and I am assuming one controls the engine management ECU the other the TCM.
Does anyone know which plug is which and if it can be piggybacked off TPS on the LM7 (LS1) engine?
I know there is aftermarket controllers around (Compushift & Shiftkits) but they are very expensive and Compushift are out of stock for the foreseeable future anyway.
I am simply hoping that someone here has already done this and has some information.
Thanks

There are 2 plugs on the TB45E TPS when it’s for an auto. One set of 3 wires is the TPS and the other is the idle/WOT switch.
Yes, you can connect another TPS in its place no problem. I initially used a ZD30 TPS with the ZD pedal for my TB45 to TD42T conversion and later fitted a 3 wire TPS to the TD injection pump but kept the idle/WOT switch on the pedal.
Do you know you have to keep the TB45 ECU connected when using the TB45 TCU to run the RE4?

Thanks John
Yes I'm aware that the ECU needs to be in place as the TPS signal is passed through the main ECU to the TCM. That said I believe it can be bypassed by re-routing the TPS wiring. I had a turbo on the TB45 and a Haltech ECU that is how we got the auto working correctly. I got a module from Haltech that was wired in between to correct the signal.
Will I need the idle\WOT switch? Maybe for kickdown?
The other question is do you know which of the plugs are idle\WOT & TPS One plug is brown the other grey as in the picture below
Attachment 85741

From memory the brown plug is the TPS. If you bypass the ECU you will need to use another source for the 5v supply. I’m sure it’s simpler to leave the original wiring in place and let the ECU do the 5v and the signal will go to the TCU through the original wiring.

The WOT position simulates the Power position on the console switch. It should hold onto gears a bit longer.
The idle position will cut out the TC lockup when you release the pedal so you don’t get a jerky reverse torque effect in the TC clutch.
If you don’t have it with the TPS, like I don’t with the 3 wire TD42 unit, you can simulate it with a 3 blade micro switch.

Thanks a lot John
The direction I'm taking is as you recommended to just leave the factory ECU there and duplicate the TPS signal from the LS loom & install a micro switch onto the accelerator pedal for Idle/WOT.
This is certainly the most cost effective solution. I will post the result here when I have it done.
Cheers Glen

Also, with mine I swapped out the TB45 TCU for a ZD30 unit and find the shifting points a lot better. Just had to get the idle TPS voltage down to 0.4v

I’ll be interested to read how you sort it out.

OK so I have been a little busy but I have the car going now.
So in summary I got hold of some great wiring schematics and a pin out guide of what each pin on the ECU does. I cut out the old engine outputs from the ECU and ensured all A/T stuff was left and wired in as it was. then wired TPS from the LM7 (LS1) to the TPS wires in the original ECU and it works fine, kickdown and all.
The Wide Open Throttle (WOT) switch (The Grey connector on the throttle body) has 3 wires and do not go through the ECU. Green\Orange, White\Green & Red\Blue.
Green\Orange = 12 Volt Ignition
White\Green = WOT
Red\Blue = Idle
So simply put at idle Green/orange is connected to Red/Blue
and at full throttle Green/Orange is connected to White/Green.
So I used a brake light switch out of a VX Commodore, it is a 4 wire always on always off switch, and put in situ so when the throttle wide open it gets pressed it connects the wires as stated above. I hope this makes sense.
Should I up-load the schematics?
Cheers