3800s/c from 1998 Grand Prix into an 86 Fiero GT 5 speed.

First, a stupid question: VSS is the same as Vehicle Speed Sensor?

The reason I'm asking is because I pulled my harness to double check everything. Here is what I found:


Both connectors have yellow and purple wires.
The connector on the left connects to C1 pins 64 and 65.
The connector on the right connects to C203 G and R.

From what I understand, the connector on the left is for auto trans, and the connector on the right is for manual trans.
Do I clip the auto trans vss off and connect the wires from C1 pins 64 and 65 to C203 G and R respectively?
Another way of asking (that may be more clear) is does C1 pin 64 and C203 G receive the same VSS high signal
as well as C1 pin 65 and C203 R recieve the same VSS low signal?

You are deep in the fog.

Yes both connectors you are holding are for VSS's. One being for the 4T65E VSS and the other being a Fiero VSS.

You are going to strip down your harness and rebuild it correct? The wires won't run in the correct locations if you don't. Yes it is a lot of work and confusing however not stripping down the 3800 harness is much more confusing and much more work.

If you are going to strip down the 3800 harness, then strip down the Fiero harness also. Then use the 'tail' that ran to the VSS from the Fiero harness since it has the correct connector on it. Same thing for your reverse light switch.

Yes your last sentence is correct for the way most people run the VSS signal in a MT. You could also run the VSS signal only to the PCM and use the PCM's speedo output, ran through a speedo buffer circuit to supply the speedo circuit to C203. The advantage of this way is that you can adjust the programming of the PCM to adjust for non-stock tire sizes.

I do sell the speedo buffer circuit at http://reddevilriver.com if you are interested. I also can sell you replacement broken connectors such as the one for your MAP sensor. (They seem like they always break)

[This message has been edited by phonedawgz (edited 03-05-2014).]

I currently have the whole harness out of the car (3800, C203, C500, and power). I spent three hours checking the wires and then I found the VSS issue. The harness needs a lot of cleaning up too, so I'll do that while its out as well.

I'll splice the wires together, clean it up and then hopefully it'll run great.