Get a dash bulb and install it into the shift light location in your gauges. Now the up shift light will come on whenever the TCC is engaged. This helps a lot to understand when the TCC disengages according to vehicle speed, engine temp, engine speed (if you enable it in the eprom instead of having it go by vehicle speed), and of course your TPS. I noticed that my tcc goes on and off when I'm on the highway because whenever I lift very slightly the TCC disengages and takes a few seconds before coming back on.
This isn't anything new but I didn't know the shift light was even wired on an automatic RS wiring harness. Sure beats watching the laptop screen!

 

Thank you for posting that, its a great idea. I hope it works in my 89 iroc.

 

Would this work on a Truck with 747?