It can depending on what you are doing with the switch. Are you opening the wire or grounding the wire?

 

I'm not sure... I'm just trying to understand the point of this other than for diagnostic purposes... Whats the difference between those two Bill?

 

Could you put an inline slice on the pk/y wire and run it to a switch then to ground

when switch is on tc is locked up
when switch is off tc operates normally

does this make sense??

 

That's kind of what I was looking to do...

 

I did it for diagnostic purposes.
The wire color is Purple with a Yellow stripe (P/Y).
If the wire is grounded the TC clutch is on.
If the wire is open at the transmission the TC clutch is off.
If the TC clutch is on the engine is locked to the transmission as if you do not have a TC and the engine will die if you come to a stop (not tested).
Normally the TC clutch does not lock the engine to the transmission until you reach 43 MPH.

 

I have one of those 4r70w transmissions that shifts hard from first to second and was thinking of trying this to help soften it while doing around town driving.

I guess if it doesn't kick in till 43 mph this would be a waist of time.

Is it possible mine kicks in too early ??

 

The 1-2 shift happens at about 10-20 MPH so yes it would be a waist of time.
You might want to check your TPS as this is the pressure sensor for the transmission. If you have high pressure then you would have hard shifts or maybe some body before you put a mod in the valve body.
A hard shifting transmission will last long than a soft shifting transmission.

 

If you are thinking of making a tester here are the diagrams of the one I made for the 4R70W.

http://i54.photobucket.com/albums/g9...sion/view3.jpg

http://i54.photobucket.com/albums/g9...sterWiring.jpg

 

Wow........
Thanks again Sub

 

One quick question Bill. I'm about to install a TCC clutch disable switch and I think I might have bought the wrong thing. I wanted to get a switch with an LED so if it got bumped it would shine in my face to let me know, but I think the light is going to shine during the wrong time...

The light shines when the circuit is closed. When I flip the switch down (turn the light off) it breakes the circuit. I didn't really understand your post so can you explain again; if the circuit is closed (light on) then the TC clutch is going to act normal as if I had never installed the switch, and if the circuit is broken (light off) then it is going to lock the TC to the engine? Is there a way for me to swap these so that the light comes on when I LOCK the TC? Here's the switch that I bought:

http://www.partsamerica.com/ProductD...rtNumber=84841

Has three prongs on the back:

--- +12v
----- load
--- ground

Any help is appreciated.

 

Okay I just installed this switch and it really messed up my truck. The disconnected position just made the shifts really soft and weird... it did not ride the gears down nor did it stall at a red light. Switched it back to on and now my truck shifts WAY MESSED UP!!

Also threw 122 code when I switched it to off:

TPS circuit below minimum 0.6 volts.

WTF?!

 

Well I'm pretty sure that I spliced into the TPS wire instead of the TCC wire. The diagram that subford posted was backwards from what you can see when you look at the harness in the engine compartment. So I finally got it spliced back together... Hopefully she'll stay... Now I'm resetting the computer and I'll take it for a drive in a few minutes... Any chance I might have caused some damage?

 

Spliced the connection back together and reset the computer. Truck runs fine now. Phew!! Scared me... I still kind of want to do the TCC mod but I don't want to deal with any more of those wires on the EEC, especially not that my TPS wire is so short, I don't want to risk pulling the connector or else I'll have to replace the harness. Can I tap the P/Y wire on the E4OD plug in the top right of this pic:



What is that plug called and where is it located?

 

I take this is the switch you bought.

No the LED will not work the way you wanted it to.
The only +12 Power is inside the transmission and you are either grounding it or not.The diagram was of the Computer Plug. The Computer Plug harness would be a mirror image and you were also one pin off.
Why were you at the computer plug anyway?
The Transmission harness does not have the TPS wire in it. This is the harness you should have been working with.

The plug you want is on the driver’s fender.

 

It is called C103 and it is not in any of the diagrams you posted.
It is on the frnder under the Master Cyl.