speedo

[Webster]

Hi, I'm trying to get the speedo to work on my '88 4.0. Took dash apart found the cable wasn't attached. There is a short section attached to the speedo, then some kind of sensor w/wires then an attaching point for the rest of the cable. What is the sensor ? Is it for cruise control ? If not, why does the speedo have wires? I thought '91 and newer had electronic speedos not 88 could it be the wrong one?
TIA
Webster

 

[martin]

The sensor you found is for the cruise control ONLY nothing else. The speedometer gets it information from the speedo cable connected between the transfer case and speedometer.

 

[Webster]

Thanks for the quick response. Since I reconnected the cable the jeep seems to die when cold. never did this before. coulde this be the reason it was disconnected?
TIA
Webster

 

[martin]

I don't understand how the speedo cable can cause the problem. You may want to unplug the speed pick up for the cruise control and see if that changes anything. The speed pick up does generate a voltage and that could be messing things up.

You may also want to clean up the vehicle grounds to help things out. I got a wire brush for my electric drill, cleaned the paint off the painted surfaces, then used ox-gard from any homecenter, and re assembled the ground. I can give you more on that if you want, locations etc.

Try unplugging the speed sensor and go from there.

Martin

 

[Webster]

Thanks again,
A little more info on the jeep, The steering column was replaced by P.O. and has no control set up for the cruise control on it (the reason I couldn't ID the parts) , but the other parts are under the dash. I guess this is why the speedo was disconnected. Are there any other parts to ID under the hood? It ran pretty good before I attached the cable (I'll look into cleaning up the grounds though). Is there any way to by-pass the sensor (I would like to have the cruise, but thats a project for another time) the original cable won't reach the speed-o w/out it. Or is that another salvage part?
Thanks,
Webster

 

[Eagle]

The speedo cable for the ones w/o cruise ran direct to the speedo and clipped right to the back, just the way that 10" pigtail section is clipped to your speedo now. It might be easier to just replace the entire cable, that will also ensure that you have a good one that won't engage in needle shake due to be dried out or misaligned.

On the other hand, I believe the only "control" for cruise on the column is the signal stalk itself. That just pulls straight out, and could be replaced with the correct one that has the wires to actuate the cruise control features. The actual controller is that yellow box under the dash, above the driver's feet.