Getting ready to get a 30' bumper pull and ProPride hitch to tow with the rig in my signature. The PacBrake electronics tie into the lock up wire at the ECM to activate the exh brake when the unit is turned on and foot comes off the accelerator. If I wanted to add a TC lock up switch so that I can lock up in 2nd gear on up (Dynamic VB modded to allow that) for towing slow up steep inclines, can I do this without inhibiting the use of the exh brake? I'm assuming that I'd leave the PacBrake switch "off" and use the lock up switch as needed climbing hills. Then when going downhill, turn the TC lock switch "off" and turn on the PacBrake. Anyone have any wiring info on this? Since the Pacbrake is initially wired into the TC lock up wire, where in that circuit would I tie in to operate the separate lock up switch? 

I removed the lockup switch when the Pac Brake was installed but, for your purpose, I don't see why it wouldn't work.     Here is the wiring diagram for what I did but it can be modified with the ground wire going through a switch then the resister to ground.  You could run it through a relay with a switch like the relay on the right side of the diagram.   The relay on the left side is for release of the lockup with the foot brake option. 

 

 

 

Wow, much more complicated than I anticipated! So, you're saying that a switch could be put on the circuit leg coming off of 87 BK between the relay and resistor? What does the momentary switch do? What part of this diagram is the PacBrake wiring or is any of it pacbrake? If not, how would I know that this wouldn't interfere with the exh brake operation?  I'm going to have to re-think my desire for this option as the wiring looks intimidating to a rank novice!

The diagram below shows how I wired my 1999 truck with a 47RE transmission in stock form (3rd and 4th lockup only) when the truck was new.  I used a momentary foot switch in series with a throttle switch.  This allowed for manual operation of any combination of convertor lockup with or without the use of the exhaust brake or the service brake at any engine rpm in 3rd or 4th gear.  I had no aftermarket computer trying to control converter lockup and exhaust brake operation.

 

The system was very effective and would be even more effective in a transmission with converter lockup in all forward gears.

 

- John

 

@IBMobile has one of the trick setups for lock up controllers ive seen.