torque lock up

hey everyone, more tcc lock up questions i have been trying to get my tcc lock up working as it should, i have a 86 k5, i replaced the tranny years ago with a rebuilt one out of a 88,apparently they control the lock up differently because my 86 doesn't have an ecm and the 88 does. power runs thru the brake switch and the pressure switch mounted on the firewall and then down to the tranny, i recently replaced the flex plate and torque converter, i thought there might be an issue with my torque converter and that was why my lock up was not working, turns out when i dropped the pan i found out the wiring harness was never plugged in inside the tranny, after i replaced the flex plate and torque converter it would blow the fuse as soon as it went into od, it thought maybe i had an issue with the solenoid so i replaced the solenoid and the wiring harness inside the tranny and the plug, still blew fuse, so i did some digging and realized they are wired differently between 86 and 88, i used the attached wiring diagram to re-wire it going to the tranny. B is not used, A takes 12volt straight to the solenoid, and D is grounded, so now the lock up definitely works but it is locking up in all gears, if i disconnect D then i get no lock up in any gear at any speed, looking at the diagram it shows D as a manual lock up for 2, 3 and 4th gears and disconnected it should only lock up in 4th, i used the stock pressure switches that were in the tranny, the only difference i can think of is the diagram shows 2 terminals on the 4th gear switch and the stock one only has on terminal, i assumed it was grounded thru the casing to close the switch, i did not wire in a on off switch or any of the leds shown in the diagram, i figured unhooking D would be the same and im not really looking to have lock up in all gears just in od, am i missing something or do i need to replace the 4th gear switch with one with 2 terminals? any help/advice would be appreciated,

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Make your life easy I did not read your post it was too long for me. You do not need an ecm to control any 700r4. You do for a 4l60e the ecm on the 88 is for the TBI and egr. drop your transmission pan,look at your lockup solenoid if it's a 2 wire great. If not order a 2 wire. Look at your 4th gear switch is it on wire or 2.Run a 12v+ to the torque converter vacuum switch on the fire wall. Run the other side of the switch down to the transmission.lLook at tge pass thru connector make sure the 12 volts is going to one lead of the lockup solenoid. The other lead of the lockup solenoid to the 4th gear switch. If it's a 1 wireb4th gear switch you are done. If it's a 2 wire ground the other pin you are done. The converter will lock automatically in 4thbif you step on the throttle the vacuum switch will unlock it. You won't need a brake switch because the solenoid only has power in 4th gear.

it is a 2 wire solenoid and a 1 wire 4th gear switch, right now i have it wired like the attached diagram of what's inside tranny and it locks up in every gear, it looks like terminal B bypasses the switches and grounds the solenoid so it makes sense it would allways lock, when i unhook term D it doesn't lock up at all, shouldn't it still be grounded thru the 4th gear switch?

mjck5 said:

it is a 2 wire solenoid and a 1 wire 4th gear switch, right now i have it wired like the attached diagram of what's inside tranny and it locks up in every gear, it looks like terminal B bypasses the switches and grounds the solenoid so it makes sense it would allways lock, when i unhook term D it doesn't lock up at all, shouldn't it still be grounded thru the 4th gear switch?

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If you use 12 volts in,and use only the solenoid and 4th gear switch. It CAN only lockup in 4th there would be no ground for the solenoid in any other gear. Verify the 4th gear switch is open when you have tge pan iff,but if opening and closing 4th gear switch,is your only path to ground for the lock up solenoid,then it will only lock in 4th gear.

that's what's confusing me, if i unhook term D the only ground i should have is the fourth gear switch so it should be grounding when it goes into od, but with D removed i get nothing, i guess maybe i have a bad 4th gear switch, is there any advantage/disadvantage to having the temp switch in the circuit? was really hoping to not have to drop the pan yet again