Tcc lockup...not the normal functional question

[frotosride]

Please correct me where Im wrong butnplease show me some proof..
ECM controlled vehicles: temp 149*f, speed 30mph, TPS steady/stable throttle and brake switch closes/ brake not depressed, are what's requires to allow the tcc to lock up plus gear for my year it's 4th gear. Now the ECM has a ".bin" file that determines when the tcc locks up and the timing can be adjusted which will operate like a carborated engines by adjusting vaccum by either steady throttle or an adjustable switch.
When the requirements are met the ECM grounds pin (A7/422) This will complete the circuit and lockup the torque converter and stop torque multiplication. Along with (A7) pin wiring is a diagnostic connection that goes to pin "F" on the ALDL.
When ignition is on or engine is running at idle and not in gear and no conditions are met the (A7)/ALDl pin"F" shouldn't show any voltage. But when all conditions are met for lock up the ECU should ground pin (A7) and lock up. A simple check would be to use a light from pin (A7) via ALDL pin "F" to ground or pin(A) ground. The light should stay extinguished until all conditions are met and tcc I locked with pin (A7) grounded by the ECM.

Now to the question/issue... As soon as I turn my ignition "key on" my light is on (A7) is grounded. No matter what condition I drive the truck including going from (D) to D the light stays on except when I press the brake. I disconnected the tcc plug from the transmission and as it should the light goes out. I then drove a few miles, turned the truck off, went shopping at the commissary and plugged it back in. No change.
So is it the bin file that is messed up.. How likely is that? The ECM is completely stock and never changed since 87. No new prom or drive train swap.
When the harness was unplugged from the transmission it shifted a lot smother into drive. Normally it would shift extremely hard as if I slaped it from reverse to forward with the brake on. Not the case without the harness plugged in. That leads me to believe that they tcc is locked as the light would indicate but why?.... Maybe pressure switch.? Or possibly the solenoid stuck but that wouldn't explain the ECM grounding of pin (A7).
Any intelligent reasoning why this would be?
As always thanks in advance!!!

[frotosride]

Pin (C7) is accuated by the pressure switch  in the 4th gear port of the valve body. This is the only likely culprit from what I can see. Based on the schematic it would send pin (A7) to ground if failed or closed.

[frotosride]

I will try to pull pin (B)/(C7) from the transmission connection tomorrow to see if it corrects the issue thus identifying the pressure switch as the issue.... I think/hope..

[Captkaos]

I am a little lost on what exactly is going on and on what?

[78BIG-TEN]

Actually I think the light would be on until the pcm grounded the solenoid

[frotosride]

I was to until the other day. Initially I through that the A7 pin didn't see power because if you look at a pin out with power charts it shows that pin A7 (ECM grounds for lockup) has no power. After looking at the diagram a million times to figure out how that's possible I got it. It isn't possible.  If you check the pin or the ALDL port (F) by grounding it you will show power. Which is what every circuit diagram would show you. I was originally using an LED at the ALDL port and based on the pin out and power on 'key' and 'engineering running' shows 0vdc. So when my light can on and stayed on no matter what except for unplugging the harness I was confused and thought I had a short.

[Captkaos]

so you are good, based on your last explanation it sounds like it is working as designed.  if you ground it, it will light.

[Dr_Snooz]

What are your symptoms?

[frotosride]

Yes it's good...once again too much thinking lead me down the wrong road. For now on its shoot then aim! But I learned more about the 700r4 and ECM relationship which will surely help with the swap. I read a lot of misinformation and ultimately figured it out on my own.. Thanks to hours on duty with nothing else to do!