700r4 (MD8) Lock up problem

[usar17]

Ok Ive been through numerous websites trying to figure this out. All I've gathered so far is that there are over 10 different ways the TCC was wired for the 700r4. Originally my truck was a 305 carb, I don't know if everything was original from factory but the title is am 1985. It's now a 350 TBI. before the conversion im almost positive Lock-up worked. Now it doesn't. Original setup included a low vacuum sensor, EGR Bleed Sol, and a controller inside the cab at the base of the steering column. Here is where I get lost and confused. Tranny has the 4 pin plug with 3 wires.

(Green) Controller Wiring to Pin A: 12V+ with Key Ign, No Brake, and Vacuum is steady.
(Blue) Brake Pedal Wiring to Pin B: 12V+ with Key Ign, No Brake
(Yellow) Pin D wiring to EGR Sol: Ground when in 3rd and 4th gears.

One side of the low vacuum sensor is getting 12V+ from (Blue) then the other side goes to the controller. I assume this is what then relays (Green) to 12V+.

ANYONE UNDERSTAND OR KNOW THIS SETUP??? lol

[usar17]

My goal is to get the new ECM to control Lock-Up. I have the appropriate PROM. just need to figure out how I can get this all to work. Or do i need to rewire the inside of the tranny 

[Captkaos]

Unless you are changing ECM's and Transmissions, neither controlled lockup, it was a pressure switch.

[VileZambonie]

Is it a factory TBI system you installed?

[sphinx]

If the original carb was one of the electronic controlled models, most early 80s GM were, then the ECM had an output that switched the TCC when the proper speed/load conditions were met.  If I remember correctly, the same signal also controlled the EGR as well.  I used a push-on push-off type button switch wired to send 12v to the TCC to test the operation of the TCC in my 81 Malibu when I replaced the carb with a regular dualjet 210 non-ecc controlled model.   I wound up mounting the switch in the end of the turn signal lever, kind of like a manual over-drive switch as I was too poor to spend any more money on the Malibu back then.  (Now I'm still too poor to spend money on my truck).  If you use a manual switch, just don't forget to disengage the TCC when you come to a stop or the TCC  will lock-up on the 2 to 3 shift and lug the engine. If the TBI controller has the proper output, you should be able to use a relay to engage the TCC.  Also I have seen some after market vacuum TCC switch units for putting a TCC trans on a non-ecc engine.  Like Captkaos said some of the TCCs were controlled with a mechanical pressure switch to read the engine "load" and activate/deactivate the TCC.