HDJ81 gas gauge half working

[RhinoRig]

I am at my wits end. I have replaced the sending unit twice, one used and the latest is brand new. I have pulled the instrument cluster and measured the gauge per the FSM. It all checks out, but the gauge will only go to half full. Once the tank is about half full, the gauge starts working until empty. The fuel warning light has not come on, but should have.

Perhaps the float is stuck on something inside the tank. It looks like tight clearances in there.

Maybe there is a short in the wiring and screwing with the resistance going to the meter. I think this is unlikely.

I think it may be the gauge itself.

Thoughts? and Thanks.

 

[fitzmooney]

You may have a corroded connector somewhere between the sender and the gauge.

 

[CycloSteve]

Check the ground at the tank, both at the sender and harness.

 

[RhinoRig]

All good suggestions. I'll check it when the wife returns. Good news: the warning light comes on!

 

[Webster77]

I’m having this same issue now where do I check the ground and these connections? Any direction will be greatly appreciated!

 

[Webster77]

Well mine has been very slow to show full for a while now after fill up and st my last full up once I got close to empty it hasn’t come off of empty yet and I put 20 gallons in.

 

[Webster77]

Anybody?

 

[RhinoRig]

We have just gotten used to the needle never going past half-full and I haven't taken more time to chase down shorts/continuity.

Have you opened up the hatch to the fuel tank and sender yet? It's on the floor between the rear seats close to the foot well. Peel back the carpet and the rest is self explanatory. Then you can access the wires and check the things above. From the parts drawings, there are probably two connectors between the sender and the dash board, maybe under the left door jambs. Those are the only connectors I haven't checked.

 

[Webster77]

Are there ground connections uon the tank under the cab? I get the ones at the sender

 

[RhinoRig]

From looking at the wiring diagram, the brown ground wire goes to connector Bd 1 somewhere inside. There three connectors between the sender and the dashboard and any of them could be the problem: BL 1, Ba1, & Bd1.

 

[RhinoRig]

 

[RhinoRig]

82412 is the fuel wire. 82182 is the luggage room wire. 82161 is floor wire. 82162 is floor #2.

BL 1 should be behind the left kick panel. Bd 1 looks like the junction between 82182 and 82161.

I have a platform in the back that prevents me from having easy access, so let me know if you find these guys.