I have read as many threads as I can find about how to wire in a switch to initiate the lock up on the Converter. However I have one lingering question. I am planning on just using the wire at the diagnostic port that comes from the computer to initiate lockup thereby allowing it to be interupted by the brake pedal switch as originally intended. But if I put a regular switch on it, then the moment I release the brake it will reengage until I turn the switch off correct?

If that is the case I came up with a simple work around:
I have drawn out a circuit that would in essence allow the use of a momentary switch that will energize a relay via ground with a constant switched 12V to the coil and create the path to ground through the brake switch. There will be a return path on the ground side of the coil past the brake switch creating a path to keep the coil energized. When the brake pedal is applied the path to ground will be lost dropping the coil and opening the contacts. This would neccessitate you to push the momentary button again after the brake was applied to reinitiate the lock up and it won't just jump back into lockup automatically. If you do want it to go right to lockup after the brake is applied, a secondary DPDT switch could be added to the circuit that initiates the relay operation that would close a switch and open the leg to the TCC wire after the brake switch.

So my original question, if I just add a switch to the wire from the computer, when I apply the brake it releases the lockup, but when I let off the brake it reengages the lockup correct? Unless I flip the switch off? Thanks!

 

For what its worth, its my understanding the the 3rd gear pressure switch will prevent the converter from locking -up as soon as you release the brake. The computer will act as it normally would and not lock the converter until the trans has shifted to the proper gear. UKPaul did a very good write up on this. I have not tried it myself so I can't confirm that it will work. If you search this site you should find the article.

Good Luck...Tim

 

I'm not sure if I understand your concern but I'll try to answer this. I've had a 700r4 in my 75 for about 4 years now. When you install it you need to replace the brake switch with one that also has a normally closed circuit so that when you apply the pedal the lockup circuit is interrupted. Apparently your concern is that it will immediately lock up again once you let the pedal back?? First of all, if you're using the brake it more than likely is slowing you down resulting in a downshift out of 4th gear. There's no lockup anywhere else. Secondly, even if it was just a slight slowdown while cruising I can assure you that going back into lockup after you let up on the brakes is not a problem you need to worry about. The only item I added that I don't hear much about is a vacuum switch that disables the lockup when you hit the throttle and the vacuum drops. It's like having another gear. Hope this helps.