I am looking for the signal wire!!! I have two wires coming out of the sender unit. A tan/black stripe and a Black wire. I measured the resistance from the tan/black wire and it showed a short. The black wire shows about 50KOhms. I thought it was the tan/black wire but now I am not sure. My books shows the black wire going to chassis gnd, but it doesn't.


Next question.... Can I run two speedometers from the one sender unit?

 

what year, model of thirdgen?

 

87 Transam

 

That's odd. My '86 has purple and yellow wires from the VSS:



Usually, GM is fairly consistent in their wire colors.

The tan/black wire is probably your TCC solenoid in the transmission, and should actually be about 35-50 ohms, not shorted.

 

I checked the resistance by unplugging the end on the sender unit and taking each leg to chassis ground. I will take the measurements tonight with the sender plugged in.

 

is your speedo not working? Could be something going on with the yellow buffer box also.

 

It was working when I took it down to replace the engine. I am adding a cyberdyne speedo on the a-pillar and wanted to also use the original dash speedometer.