700r4 TCC direct running on manual switch, ideas?

[libtec]

Hi again. Thanks for looking.

I need to run my TCC off a manual switch instead of relying on the suburban's inputs and computer to tell the clutch when to lock and unlock. The tranny has two wires going into it through a common junction block. Can anyone tell me how I should wire in a twelve volt signal straight off the battery to these wires to make the TCC work only when I want it to? Are both wires for the TCC, one hot one ground, or is it grounded inside and I should only hook up 12v to one of the wires?

I do plan on running the signal through the brake switch so it will unlock if a moose hops out in the road. I only plan on using the TCC on the highway so a manual operation will suit me just fine untill summer comes back and I can trouble shoot why the system isn't working in the first place. A garage would be a nice thing to have right about now.

Thanks for the input!

John.

[DmaxMaverick]

The latest model I've done it on is '85. I don't have '90 a diagram in front of me, so I'll shoot from the hip, on the assumption that the '90 is somewhat similar to an '85.

On the '85, the TCC circuit has many switches/connections inline with the TCC. From memory, they are: brake switch, ECM, ALDL, 1st gear, 2nd gear and pressure port (tranny).

What I did was follow the circuit from the ALDL and bypassed all the switches, all the way to the TCC, but couldn't bypass the pressure port, so it has to be in there. I placed a cut-off at the brake switch so I could include it or not, depending on my mood (downhill braking). I installed a push/pull switch on the shift lever (like a 2 speed rear switch) to complete the circuit.

The result was, in 2 hi, shifter switch selected, TCC lock up above about 34 MPH in any gear but 1st (1st wouldn't make it to 34), and it would hold lockup until it got below about 30. Lockup does require go pedal input (TV cable--pressure port) of about 10%. In 4 lo, it worked the same, but the lockup occured at about 8 MPH (could be a harsh 2-3 shift if not expecting it).

I have more info on this if you need it. I considered doing the same thing on the '95, but the 4L80E is a different animal and seems to manage TCC pretty well by itself, as it's only 2wd and used mostly on flatland.