90 chevy speedometer wire

Just finishing up my 5.3 with 4l60e swap in my 1990 Chevy Silverado. I ordered a PSi harness for the swap an everything was super easy to install an was very clean. My only gauge I don't have work right now is my speedometer. On my harness I have one wire coming from harness labeled speedometer . I cant seem to get anything to work. I know on 90 the instrument cluster has the drac built in . so my question is where do I need to hook the single wire for my speedo to work?? I have searched on forums several times an still really don't get a clear answer

I can't tell you for sure. I can tell you that if you still have the "moonie" gauges and not the needle style (92-94) then you don't have a DRAC. You have a VSSB (vehicle speed sensor buffer) and it is built into the cluster.

yeah still have moonie gauges. so where would I hook single wire in instrument cluster to get a reading

do I have to take the old yellow an purple twisted wires that went to old tran an tie them into new harness to get gauge working?

Got it working. Thx for help. Just so others know u connect like so. On your vss output from 4l60e the green wire goes to purple on gauge cluster n purple to yellow on cluster. Didn't need to connect Speedo wire from New ls harness

Potter, I should have logged in sooner, thats exactly what I had to do with mine.

I am wondering which wires on the 4L60E you are referring to? Do you have a picture? Are they spliced in to the speed output to the PCM or did you cut them and only run them to the purple/green wires?

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Originally Posted by codyvette

I am wondering which wires on the 4L60E you are referring to? Do you have a picture? Are they spliced in to the speed output to the PCM or did you cut them and only run them to the purple/green wires?

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After waiting for a bit, I gave up and just tried it. The output wires from the transmission (purple and green) can feed the computer and the gauge in the dash. They are parralleled.