Hey all. I'm gonna be putting a dakota digital box in my car later this week to recalibrate the speedo and i was wondering if someone could tell me where the most convenient place to cut into the VSS harness would be? I did a search and i can't find any specific info on where the wire comes into the car from underneath, and where it runs / splits to the cluster / ecm.

Maybe it's really easy to find once you're in there, but in my old age i like to have an idea of what i'm going for before i start tearing things up.

 

I am guessing that you did a auto <> manual tranmission swap?

I ended up cutting the old vss connector off of my harness and running the wires from the harness and the new vss wires off the tranny up throught the old automatic cable shifter hole in the tunnel. I mounted the dakota box just in front of the t56 shifter, and that gave plenty of room for the console to be installed as well. I reused the rubber grommet from the shift cable as well, so the hole is watertight.
That way, I didn't have to cut into the harness anywhere else, since the old 700R4 VSS and T56 VSS's are different.

 

No, i didn't do a tranny swap, i just have more use for an infinite accurate solution to recal my speedo after a gear swap than swapping speedo gears allows, thus the dakota box.
As i stated in my post i'm trying to determine exactly where the wire runs into the car stock so i don't have to start tearing everything apart to find it.
bttt...

 

z28s dont have a vss https://www.thirdgen.org/newdesign/tech/unlimited.shtml

 

VSS is the Vehicle Speed Sensor

I can assure you that Z28s have these (all of them.) The early cars VSS is on the speedometer and sends the speed to the ECM. The later cars (like mine) have the VSS on the tranny which sends the speed to the speedo (electronic) and ECM.

You're thinking of the speed limiter. I'm not even going to explain those to you...

 

Ed,

What are you doin' chief? You just need to ask the right person I use to have one of those boxes in my car before I got smart and just installed the right tranny speedo gears. Drop the ECM from under the dash, locate the proper wires, and just splice the box in there. You can get the diagrams of the wiring harness at diy-efi. Go to the GMECM site and then choose ECM information.

Tim

 

Um, I may be way off here so pardon my ignorance and lack of memory if I am....

On a T-5, at least mine, there are TWO sensors. One is the VSS and the other connects to the speedo gears. They are not directly related.

 

my bad , yep i know what your talking about mine is on the tailshaft of my tranny by the speedo gears, my apologies

 

I'm pretty sure that all the tranny related wires cross over the top of the tranny from the drivers side to the passenger side, run up under/around the aircondiditioning stuff then through the passenger side inner fender panel around and down to the kick panel on the outside of the car into the car through that huge big block gagle of wires that enter the car from the outside by the drivers side kick pane. That was where the tranny wires entered the car on my 86 T/A's 700 R4 tranny. I put a TCI lock up converter kit in my tranny and eliminated the computer all together. I will rerun my wires in the heater wiring firewall hole. Since no wires now need to run through the passenger side kick panel.
Be cool!
"TEACH"

 

This is a preliminary follow up, i won't know for sure if it works until tonight or tomorrow when i wire it up.

I referenced the wiring diagram as per tim's directions and sure enough the VSS only hits the ECM and the speedo and CC feeds come from there. Thus i'm going to splice into the harness right before the ECM and i should be set.