700R4 torque converter lockup

[carolinafan4life63]

Ok I had a post earlier about the bulbs for the indicator lights at the bottom of the instrument panel and a wire coming from the tranny.

There is one single wire coming from my 700 R4 (drivers side of vehicle) up to the brake switch that the pedal contacts to operate the brake lights. there is another male connector for a wire to go to where nothing is hooked up. should there be a wire going to a 12 volt source from the brake switch so that the torque converter will lock up . I am assuming this wire coming from the switch on the tranny is for this purpose but it seems as if there should be a wire from a power source going to the switch also so the switch on the tranny would operate. please if anyone can help me , i sure would appreciate it , i really do not want to burn up my transmission. thank you

 

[Blue85]

The brake light switch and the tranny lock up are two separate switches on the brake pedal linkage. There should be two power wires going to the tranny and probably a third wire coming back out (which is used for EGR or something). One power wire should be hot all the time, except when the brake pedal is pushed. This should be the only thing that can stop lockup in 4th. The other power wire usually goes through the vacuum switch near the brake booster - this is for your 3rd gear lockup to only happen at lower engine loads.

If you don't have lockup, don't use overdrive.

 

[carolinafan4life63]

ok here are a few pics to see if ya'll can help me . my transmission shifts fine but I cannot feel the locking -unlocking of the torque converter. The previous owner did a real hack job on the wiring and I am just trying to fix it and make every thing work right.



the first pic is of the switch on the left of the brake pedal bracket.......it has one plug with an orange wire and a black wire in it

then there is the green wire coming from the tranny to this swith.....where does the other terminal next to the green wire on the switch need to be hooked to?

then the second pic is of the switch to the right of the other switch on the bracket......it has a hose of some sort(vacuum i assume) and a plug with a blue wire and a tan wire connected to it. the blue wire is cut so what does it need to be connected to? or is this for the cruise?

i pulled them from the bracket to get pics of them

 

[carolinafan4life63]

ok , So I went to bowtie overdrives.com and they had a brake switch converter lockup wiring diagram in their 700R4 page. so i have the plug for the lights on the front two male connectors , the third connector goes to a keyed on 12 volt supply and the last connector is a single wire going to the transmission.I hope this is correct.



now for the next question.......
What is the other switch with the two wire connector(brown and blue wires) and the vacuum tube on the very rear?? I have power to the brown wire , but the PO had cut the blue wire. what does this switch do??

oh , and how can I tell if the converter locks up like it is supposed to??

 

[carolinafan4life63]

ok so I traced the vacuum hose from the back of the switch in the second pic in my original post. It goes through the firewall and is taped/bundled together with a group of 5 wires and runs all the way to the front drivers side of the truck , all the way to the firewall. the wires have a square factory plug on the end. do you think that maybe this was the cruise control hookups? I have done quite a bit of searching on here about this subject and keep hearing about the lockup being controlled with a vacuum hookup on the fire wall , but I dont have anything of the sort on mine. I really could use some help guys.

 

[Blue85]

oh , and how can I tell if the converter locks up like it is supposed to??

Get the truck into 4th gear, keep the throttle steady and tap the brake pedal just enough to trip the switch. If the rpm goes up, that is the converter unlocking. You usually can't feel it lock and unlock (not like shifting a gear) but the change in engine speed is noticeable if you are looking for it.

If you have a tach, just look at the rpm when you are cruising (i.e. should be locked up). If the engine speed changes without the vehicle speed changing (like when the load changes to go up and down hills), the converter is unlocked. If you can change your throttle position without the rpm changing it is locked.

Another way to tell is to drive it a long time in 4th gear at low rpm. If the tranny overheats and shoots ATF out, the converter is not locking. I don't recommend this method, though.

 

[Blue85]

I don't think the switch with the vacuum hose has anything to do with the lockup.

How many wires come out of the tranny? 3? If one goes to that switch, where do the other two go?

 

[Blue85]

And here's the insides, but there are many variations!

Sometimes the solenoid Neg is tied to the chassis and terminal B is used to bring out the lockup signal.

What you need is to get (brake) switched 12V to terminal A. That is the most important part because it gets you locked up in 4th.

 

[carolinafan4life63]

there is only one wire coming out of the switch on the tranny , a green one. looks like the previous owner had it wired to the brake switch , it just wasnt hooked up. I used a diagram off of bowtie overdrives to wire it up correctly to the rear terminals on the brake switch. I took it for a drive today and when cruising in 4th gear , if i tap on the brake pedal the rpms jump up just a bit , so i assume it is working correctly. the other switch with the cut wire and the vacuum hose I pulled out and there was a part number on the side. I looked that number up on the internet and confirmed that it was indeed the switch for the cruise control. thank you for your help. if you have anything to add that i may have overlooked , please let me know.