79ChevyVan

Hi,

I have a 79 Chevy Van that I use for pulling my travel trailer. It's in great mechanical & fair physical shape. I put a rebuilt 400 engine & a Carter 600 CFM Carb in it a few years ago & it runs so fine I just can't bring myself to retire it. Add to that the rumble of true dual exhaust & I guy just goes to heaven.

Here is my problem.

I recently purchased a dead 87 van (Engine & Tranny both gone, body shot) to use for upgrading my 79. I am trying to take the cruise control out of it & put it in the 79. The 79 has the old one button cruise with the module on the engine. It works about half the time & not very well when it does.

I should mention here that I have 30 years of electronics back ground so wiring & schematics is old news to me.

I got a schematic for the 87 cruise from Mitchell.

I removed all the wiring from the 87, the cluster & all the hoses. I have installed it in the 79 but I have a problem. It won't engage. I did all the diagnoses according to Mitchell & it seems my problem is related to the Speed Sensor. I am supposed to get from 0 - 4 volts when the wheels are turning but I get nothing.

ECM means Electronic Control Modual for the cruise.

There are 2 plugs that go into the green box (speed sensor) on the back of the cluster. One has three wires, Pink(power), Black(ground), Dark Brown(unknown) & the other has one wire, Dark Brown(VSS on ECM). I think my problem is the Dark Brown wire on the 3 conductor plug. At first I thought it was the wire that went to the VSS on the ECM but it isn't. It's not shown on the wiring diagram. I have physically traced it through the firewall & along the harness till it goes past the engine & back up into the rear compartment. It does not appear to go anywhere. It does not loop to ground or get positive voltage when I turn on the ignition of the 87.

Any thoughts?