Can a speedometer have the option of being cable or electric driven? Well, since I bought my 89 S10 Blazer Sport, the speedo wasn't working. When I hooked it to the scanner, I could read the speed, so I thought it could be a bad connection in the cluster's plug as I had that issue with different things like the heater's speed switch, the wiper's connector in the hood, the rear interior light' switch in the trunk,... All that because the truck was parked for 6 years without use. So I removed the cluster today and found out that there's 3 cables (red, black, and green) coming out of the speedo that are not connected to anything, and when I took a closer look, I found out that it has that hole for a speedo cable! I turned it by hand and it worked. Took a look inside the dash and saw a wide plug with custom connected cables to the temp gauge and didn't see any speedo cable! So I guess that the previous owner changed the cluster to an older one. But what are these 3 cables? Can I choose between cable and electric or are these cables for something else that has nothing to do with the speed gauge?
I attached some pics.

 

Those wires are the VSS, Pretty sure in 89 it was still cable driven. Wanna say 90 or 91 was the year they swapped over to electric speedos.

 

What's a VSS, and if it was cable driven, then what's the multi-pined wide connector that I have behind the cluster and how was I able to read the speed on the scanner? Plus that I have that speed sensor under my truck! Wish I took a photo of that plug in my dash behind the cluster. I'll remove the cluster and take a shot of that connector on Saturday.
So, where should I connect these wires?