After hearing that it could be ruled down to those two things…How can i go about testing the return wire or PCM?
everything gets me one step closer to resolving this issue and never having to deal with this again.

 

If you get wire piercing leads you can test any wire. If you don't have long leads you can pic two locations on a wire about 3-4 feet apart and test each section from the sensor to the pcm. I would check the connector first before doing all that.

 

An easy way is to simply unplug the connector at the PCM, put a jumper wire between those two wires, then test resistance of both. Should be near zero. If it is open, then you need to get creative, to test the wires individually.

 

What is the sensor on driver side of transmission near rear of trans? I've replaced that on a '99 1500 before and IIRC it was causing speedo issues, but I get it mixed up with the diff sensor as far as function.

 

Output speed sensor. Probably..... I really couldn't tell ya if the PCM uses that for vehicle speed, or not.... Dodge did some major shuffling of how things work over the years..... The sensor itself is cheap though, couldn't hurt to replace it....

 

And should i check for resistance or what should i set my multimeter to??

 

From the 1998 FSM:
The sensor on the transmission is used solely for transmission control.

OP: Besides checking the wiring you also need to check that you are getting a useful signal out of the sensor. Sometimes things like rustjacking affects sensor position and output. Did the speedo ever work ?
Edit: Did you ever check power at the ABS module ?

 

Before it quit working, was the speed shown off from the actual speed? Is the odometer still working? Before I found the problem with my '96, I tried checking the solder joints on the speedometer. I watched a video of a truck about your vintage where the speedometer was reading high. He was going 35 mph and it read 90 mph. The solder joints on the back of his speedometer had cracked. He showed how he resoldered them and it cured his issue.

You might pull your speedometer and run your Mark 1 eyeball over it and see of there's an issue with your unit.

 

Before it quit working the speedometer needle would jump and sometimes cut out and come back. The odometer would cut in and out depending on if the speedometer was working. Now its gotten to the point where the speedometer doesn’t move unless i do a cluster test and the odometer doesn’t go up neither

 

Do all the other gauges/lites work?