My gauge started to act erratic, bouncing around when it should have been just under half tank. I filled my truck, and it went to over the full mark, that never happened before. SO, I pulled one bed board and removed the sending unit. I checked out the sending unit on the bench. It is 0 ohms at empty and 30 ohms at full. I replaced the wire from the gauge to the sending unit so I could route it better like the original wire was. It is 16ga and I soldered the connectors and put heat shrink on it. I have a ground to the sending unit already. All back in place but the gauge still read over full. SO, I disconnected the sending wire from the back of the gauge and turned it on. No response. I have read the tech tip about the fuel gauge diagnosis procedure. Well, after I powered it up without the sending wire attached, I could not see the needle. SO, I went out to the garage today to look at it again an tested my sending wire at the gauge end and it is good. After messing around trying to get the gauge to respond to something I found that the needle is GONE, MISSING, LOL. I shined a flashlight into the gauge cluster, and it is nowhere to be seen. This was a brand-new gauge cluster that has about 900 miles on it. I did not mis wire it or any such thing trying to get it to work again, mostly just using my ohm meter to check things, like gauge cluster ground and voltage to the gauge. Funny, the gauge is actually broken inside. I did hit a bad bump in the road just before the fuel gauge went bonky. New one on order already. I have an old one that seems to work, so, I might just hook it up outside the gauge cluster and see.
Well, I thought I would post my findings instead of adding to the other post. I took an old gas gauge that I had and hooked it up to the sender wire in my dash, then I put a jumper from my fuse block to the gauge, and a ground jumper on it too. I turned on the key and it read correctly as far as I can tell. My 47 3600 has the in frame 16 gallon tank that came with the truck. I have about 45 miles on it since the last fill. At 14.5 mpg it should be just above 3/4 tank, and it was. I'll have to drain the engine and disconnect the temp gauge and remove the gauge cluster on Monday.
Last edited by lumbersawyer; 10/22/2023 8:58 AM.
