Well, like the title says, I have an 88 300zx with an analog dash. I installed a mint dash complete with harness and now the only gauges that work are the center dash pods. Now, when I compared the wire differences, I noticed a white wire was spliced into the old harness on the driver side large white connector. It had been spliced into the red/green wire. What exactly is that wire?

Oh and where the heck is my speedo sensor located? Here I am trying to check the dash end of the cable and to my and my dads surprise....no cable to be found.

 

What color is the instrumentation of the cluster you installed? What year is the dash wiring harness you installed?

The speed sensor is on the pinion gear assembly that's on the tail of the transmission. It's an electronic signal.

 

Its an 88 non-turbo cluster. Color is white...Orange with lights on. The replacement padded dash assembly with harness was from an 87 non-turbo. I basically installed my cluster in a new dash and harness.

 

Then you will have to check the FSMs to see if there are wiring differences by comparing pinouts. Or go back and put your original harness into the new dash.