2015 Coronado - No Speedo or cruise control

Maybe these will help you. I'd pull the vehicle harness and ohm across 556 and 557 to start. Should be 700-1300'ish, IIRC.

Make sure that is good, then move on to the data link. Just takes a few minutes, and is easy. Also look at the individual female terminals for 556 and 557. It is very common for the spring to lay back and not make good connection.

Then you'll know Vss Wiring is good. 2 lead sensors, and 2 sensor systems used one of those leads to drive the speedo.

Most later trucks the speedo waa driven by an output from the ECM, but my 98 DDEC 4 is also is a 2 sensor system.

 

I did repin 556 and 557 because the very first thing I thought of was loose pins. Resistance was the same at the ECM connector as at the sensor connector. Speed signal is coming from somewhere. My scangauge reads road speed through the 9-pin. In my head I think the problem is between the ECM and cluster. I don’t know how or where to start. I’m assuming that the wires go to multiple places throughout the truck including the cluster. No idea what to look for to confirm the circuits are good.

 

Wish I had more info, but I've not worked on one of the gliders. I would think you're probably correct. Is there any source for reliable wiring diagrams for the body?

 

I’ve offered to pay techs for all the wiring schematics for this truck but they say it’s more complicated than I think. I’m not in that world so I wouldn’t know.

 

So now what does the range selector in the transmission have to do with the speedometer?
I changed the shifter boot so I don’t lose any toes to frostbite and when I aired up the truck to make no air was leaking, I was moving the range selector up and down and the speedometer started jumping and fast idle shut off. I was able to duplicate it many times. every time it shut off my fast idle.
Is my issue something as stupid as a loose yoke? It doesn’t move around like it’s loose. And I can’t turn the tone ring.

 

Did you ever try that before? I have seen speedo needles move changing ranges before as the gears move a bit. Do not recall ever having fast idle set when I did that.

 

This was totally random when I was making sure everything worked after removing the shifter knob to change the shifter boot. I had the fast idle set to air up. And after the second flick of the range selector the Speedo jumped and the engine went back to low idle. I was able to make it happen multiple times. I don’t know if you have read the rest of this thread. I have not had a speedometer or cruise control for a while. This is the first movement of the speedometer except for when you turn the key on in a year.

 

When you replaced the vss, did you bottom it out? Only needs to be backed off a tiny amount, so it’s not in full contact, I’m sure you did.

 

My opinion....ohm testing wire circuits is pretty pointless as one single strand of wire will show it to be good. Make some load test lights with a 9004 style bulb or even a 1156 bulb and see if the circuit can power a load.

 

This! And every other mechanic/tech needs to understand the importance of load testing and measuring voltage drop.
Good point.