90 silverado speed signal

[70sguy]

I am wondering If anyone knows the location and color for the vehicle speed sensor on a 90 silverado. Also if you know where the reverse signal wire color and location. I have searched all over the net and I find nothing. If the only place to tie in is at the speed sensor itself, then which wire is it?

Thanks

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[adulbrich 5,000+ posts]

The speed sensor should be off the transmission case iirc. Why do you need to tie into that?

 

[70sguy]

I have a pioneer Avic 5200 and the harness has a pink wire that goes to the speed signal. The instuctions say to tie that in for best operation of navigation. I also saw some posts that other ownwers of that radio said it works a lot better with that hooked up. I am aware that the VSS is on the ***** case. It has 2 wires. How do I determine which one to use? Also is it best to tie in right there at the VSS or should I pick it up elseware?

 

[adulbrich 5,000+ posts]

It depends on if the speed sensor sends dc or ac signal. Being older, I would guess that the sensor just has regulated positive voltage sent to it with one wire, and depending on how fast you're going the resistance of it changes, and it sends back a dc voltage through the other wire. In that case, it wouldn't be too difficult to probe the wires and you'd tap into the one with varying voltage. I wouldn't think it would use AC, but I know mid-2000's alternators are pcm controlled. The pcm and regulator communicate with sine waves and voltage is signified by the duty cycle of the wave. If it was AC, the wire you picked wouldn't matter.

I have no idea which style the sensor you have works off of though, sorry.