Which are you testing? Do you have your probes on the pins from the sender? Or from the harness going back there? Can't ohms test the harness going forward, it will show as open. Need to turn the ignition on, and short the two pins together, see what the gauge does. (best not to leave it like that for long.)

Where did you get your wiring diagram from? G119 is one of the grounds you are interested in..... (if that's accurate......)

 

I got my diagram from my Haynes manual. And I was testing the probes on the sender itself. And it wasn't reading anything the meter never moved. I just climbed up under the bed and could see the fuel pump. It's really tight but I can get a tester in there. I had the key off though. So I need the key on to test the ohms. The meter works I tried it else where before I went under. But I filled the truck up and the gauge went full. But after a few miles it will go down and flicker violently around empty . Also where Is the location of g119 I can't find it. Is it the one on the cross member behind the driverside bumber? And when u say shorting the pins you mean short the harness pins with a paperclip correct?

 

When ever you are measuring resistance (ohms), power cannot be on. Does the Haynes manual have location diagram for the ground points? I'd suspect that G119 is either at the engine, or the body. If you measure resistance between the transmission and the BK/WH at the tank connector, and the meter shows 0 (or almost zero) resistance, ground wire is ok.

Yeah, paper clip will work if you short the dark blue and black w/tracer. But, just to be on a safe side, you could use a flat fuse, couple of crimp connectors and piece of wire. Basically you just extend the probes of the fuse with the wire, and push the wires to the connector to short the DB and BK/WH. This way, if you accidentally connect pump feed to the ground you just burn the fuse. I use that setup at work every time when I test the wires if there's even slight possibility that there is voltage on some wire.

 

I have acouple inline fuse holders I can make a perminent tool for this situation. Some crimps and 2 paperclips and some wire. What size fuse u recommend

 

5 amps will do fine.

 

Sorry for the quick hijack, do you know if these numbers hold true through different years? When I switched my 97 cab to a 98 chassis my fuel gauge went goofy (clear full = 3/4 on gauge, 10 gallons used = empty with 34 gallon tank), and I haven't found much info to show a difference.

 

Looks like the numbers hold true from 94 to 97. Not sure about the electrics on 98 w/gasser, I know that you could get 98 truck with rear doors and 12 valve Cummins w/P7100 injection pump (which does not need electronics to run), but 98.5 got the 24 valve ISB engine which brought the electronics to control the VP44 injection pump. On those the fuel gauge signal goes through the PCM, when at the older models signal came from the sender straight to the gauge. But I assume the 98 would have the updated electrics from the start.

 

A lot changed between 95-96, and then again between 97-98. A bit more changed from 99-00.......

 

Thanks for the info Heikllm, that's more than anyone else has been able to tell me (my phone don't like the fsm)

Hey You, I know 'alot' changed between 97 and 98, that's all most people will tell me