Speedometer Speed Sensor 1985 C20

[Johnret]

Attached to my dash cluster is a Large green speed sensor. I can not find under the dash where this thing plugs into. Attached is a picture of the sensor. Connecting to the cluster was obvious, but can find anything under the dash to plug the module into. Any help or pictures of the correct connection would be of great help.

[zieg85]

Used for cruise control

[bd]

The buffer mates with one black colored 3-wire connector having black, brown, and pink/black wires and one black or natural colored single-wire connector having a yellow wire.

[Johnret]

I understand it is used for cruise control. The problem is, I can't find the connector to connect to the speed sensor. I have looked under the dash and see no loose connectors. If possible could someone take a pic of this thing connected or point to the location where the connector should be located. thanks for the replys…..

[Chevy Guy]

Hello Johnret,

First attempt to attach an image to a reply, hope i'm successful.

When I was trying to find out what the plugs look like, this is all I ever found as to what the plugs that plug into the module look like, hope this helps

[Johnret]

That is great, thanks much, I'll check it out tomorrow.....

[Johnret]

Well still no connectors for that speed sensor. I am thinking that the factory cruise control system was replaced by an after market system. My cruise control has a wire that runs through the firewall down to the transmission and is attached to the speedo cable and connected into the transmission. I don't see that configuration listed in the factory manuals for the cruise control. The factory manuals don't even mention a cable of speed sensor attached to the speedometer cable for my configuration.I suppose the orignal owner may have had some problems with the cruise control and had it replaced. The control mudule on mine doesn't appear to be factory either. When I took it apart (2.5 years ago) the control module was installed by hanging it from the steering column with red electrical wire, not exactly a factory job. So when I get the truck running again, maybe a month or so out, I will see if the cruise is working and if so, I guess the speed sensor on the dash was just left hanging after the after market cruise was installed....

[MIKE S]

That sensor is also used to tell the ECM of your speed for certain emission systems. Also if you have a lock up type torque converter it is used to determine when to lock up. That is the way it is used for California emission systems. 49 state doesn't use the same set up. If you can't find the mating connectors under the dash, the former owner may have put a used cluster in it at one time it may have been just attached to it serving no purpose for your truck.

[Johnret]

Mike, That is what I am counting on. I see once the truck is rolling again.. thanks for the reply