Speedometer issues.

[Greenman666]

So my speedo doesnt work. I'll go over the history of the car first. It's an 89 sohc, was swapped to manual by the previous owner. Parking brake light has always been on. Got the car in 2006, speedo stopped working about 6 months or so later. The transmission is supposedly from a 92. Tested the vss yesterday, using alldatas procedures. Tested good, gear looks good. Every once in a while the brake light fades away and the speedo starts working. Then I hear a slightly high pitch buzz from around/under the gauges. When I let off of the throttle, the brake light instantly turns back on and speed drops to zero. I was checking the trans harness and I had two vss plugs. One has the yellow/green, yellow/black. The other is yellow/blue and yellow/black. The green is for auto and blue is for manual according to my diagrams. I'm now lost, trying to figure out the trans harness I have from the diagrams is killing me. Anyone know of a way to wire the speedo to the gauges to eliminate the possibility of a short, to make sure the gauge itself is good? The trans harness appears to be a hack job and is now on my toolbox, drove home and it's the same as before I removed it. Any ideas at all would be greatly appreciated. Sorry for the long post.

[OutToWinPAHC]

Speedo two wires, one goes to chassis ground, the other goes directly to the cluster, if you pull the cluster you can see the back the speedo has 4 screws which make connection. VSS in, DSS out, 12+, ground. Vss goes to vss in, then DSS is the digital signal sent to the ecu.Now if you want to go straight to cluster zip the vss screw out of the speedo, terminate it there with a eye connector then trace the trace to the old in wire and you can use tape to cover it from making connection with the dash plug.

[Greenman666]

Hmm. A bit confused. The cluster gets the direct signal from the vss, then speed signal goes to ecu? So you're saying to run a wire from the vss to the back of the clusterusing an eyelet crimped to said wire then tape over it. Is that what you mean by terminate it? And I thought the vss was an a/c reading like an abs sensor.

[OutToWinPAHC]

It is an AC signal the VSS is a electromagnetic motor spun backwards aka a generator. One side goes to ground, because the cluster also uses chassis ground, and the other side goes to the cluster, with that the speedo will work. But now you have the old factory wiring going from the old VSS wires to a connector in the front of the car, to a connecter on the body to a connecter under the dash to the cluster and your trying to bypass this, because you question it. So remove cluster, flip over and you will see the 4 screws that hold in and make the electrical connections to the speedo. One is battery, one is ground, one is in, one is out. With the VSS connected to chassis ground on one wire run the opposite wire directly up to the IN of the speedo, once that is done you will want to visually follow the tracing to the connectors for the cluster, locate the terminal and cover it with and insulator that way when you plug the connector in your not hooking up the wire you think is bad that is causing you to do this.