The speedometer and fuel gauge are not working properly on my 94 1500. The speedometer is stuck at 0mph when driving, yet the odometer and trip meter work fine. The fuel gauge is below empty and the fuel light is constantly on whenever the truck is on. Would a ground be the cause of these issues or could it possibly be a sensor or the sending unit? I noticed that small black and green ground between the rad support and front left fender was snapped, but i am unsure what it controls. Another odd issue I am having is that whenever i am at any pump, it clicks to stop even though the tank is not full. The filler neck had a couple pinholes between tubes and i had patched it with jb weld. I tried to fill up again and the pump did the same thing. I am open to any advice as I am very confused.

 

You can try this process with your gauges to see if it helps -
As for your ground wires, they should be repaired or replaced. Those are body grounds.

The fuel fill tube should also be replaced to prevent leaks and help with your refill woes. You can find them at local pick and pay salvage yards pretty cheap and they are easy to remove. If desired, you can purchase a new one - Rock Auto sells them as "fuel tank filler neck".

 

He has a 94 it's not can buss dash.
There is an issue with the gauge itself.
Fuel light is controlled by the PCM it reads the amount of resistance it gets from the sender. The sender in most likely the problem.

 

The first time filling up about 5 gallons i did not run into this issue. After that, the issue started occurring before and after the patch on the filler neck. Could the breather on the filler neck be plugged? When i put gas in with a regular can it seem like it goes through fine with no leaks or other issues.

 

If it is an issue with the actual gauge, would the dash have to be removed to diagnose the issue? I am pretty sure there is a sensor on the top of the rear diff but that has not been replaced recently that i know of. I was hoping that wasn't the issue with the fuel gauge. Would it be more beneficial to just get a whole new fuel pump?

 

Some nitpicking, as this is a "analog" dash the low fuel light is controlled by the instrument panel itself. It simply lights up when the resistance from the sending unit gets too high (there is some circuitry to make it not flicker from fuel sloshing around). Once the fuel sending unit or wiring is fixed this will work too.

 

Look at the wiring for the sender, It goes to the pcm when the resistance is(low or high depending on how it's set up) the pcm turns the light on. My sender took a crap about a year after i replaced the pump. I was curious about how the light worked so looked it up in the service manual. Since the odometer is working and speedo isn't it's in the gauge. If the sensor on the rear went it wouldn't do anything and the abs light would come on(it uses the same sensor).

 

According to your profile you have a 1996 but the OP has a 1994 so let's not confuse the OP. They don't even have the same PCM. Agree on the speedometer being a gauge problem as there is only one input signal for both.