staleyracing

I just got my 3rd gen back from my dads getting painted. I hoped in the car and fired it up and started driving. I then noticed the Speedo isnt working. All my dash lites and other gauges are working. But the speedo isnt. Any ideas where to start? I havent had the car for 2 years so Im a bit rusty on where to start looking. So far ive just looked for burnt fuses.

calaban

I don't really know how to tell you to diagnose it, but it's got to be one of only a couple of things. The VSS at the rear of the Transmission, the Wiring to the ECU/Speedo, or the Speedo itself. If the cruise works it may be the speedo itself. I think that the signal goes from the VSS to the computer. Then the computer sends the signal to the speedo for the display only.

Good Luck!

BigBadLou

Calaban is correct. On the TPI models, the VSS signal travels from the back of the transmission (driver side, in the tailhousing, yellow & purple wires) forward, through the engine wiring harness and the right fenderwell to the ECM under the dash (passenger side).
The ECM serves as a signal splitter and provides the information to the cruise control module and the instrument cluster via the C207 connector.
So as Calaban points out: if your cruise control used to work and it still does, the problem is not in your VSS but likely in the speedometer or the instrument cluster connectors.

Let us know what you find.
Lou

Two diagrams to help you out:
Gauges: Speedometer
VSS

staleyracing

Ill let you know what I find out. I have to put it all back together now. I took out the instrument cluster and and cleaned all the circuits on the back of it. Ill put it back together and check the cruise control first.

thanks