Electrical Question/Fuel Gauge

[KingPrat]

So I (finally) got my truck back from the mechanic after a 6 week jaunt getting the head gasket redone. When I brought it there, the gas gauge quit on me. Went to full empty and the light is blinking.

The mechanic chased down the wiring and tested the sending unit. I'm curious about their diagnosis:

"Tested resistance of sending unit, tested at 200 ohms, full tank reading. Tested 5v power on yellow wire, 5v present. Tested Ground on brown wire and found no ground coming from instrument cluster. Cluster failure is usually on circuit board and will have heat damage. Will need cluster removed for repair."

I am very unknowledgeable when it comes to electrical things. Can anyone decipher that? Does that sound right that the ground would come from the cluster?


Also, with that in mind, is the mileage stored in the cluster or in the computer? If I swapped in a different cluster, would the mileage still be correct?

 

[jgue467]

Don't know about your first question on the cluster. Perhaps someone else on here knows and/or you can start getting familiar with the FSM, it's all over for free.

Now the 2nd question I do know the answer, the cluster keeps the mileage. You'll get whatever the 'new' cluster has but I from reading what you said mechanic said, it does not sound like you need a replacement cluster, just a repair to it. Luck. :cowboy:

 

[KingPrat]

I had the cluster out the other day doing an LED swap. Can anyone point me in the correct direction as to where the circuitry is for the gas gauge?

My brother is an electrical engineer and he said the board on the back looked especially clean...

 

[alanflies]

http://www.toyota-4runner.org/3rd-g...d-gen-fuel-gauge.html?highlight=bad+gas+gauge

http://www.toyota-4runner.org/attac...our-spastic-3rd-gen-fuel-gauge-t-el010-00.pdf

If a calibration doesn't work, check your vin against the vins listed in this TSB. Then you will know if you need repair 1, repair 2, or both 1 and 2.
Just had to do the in tank sending unit on my wifes 99. but you may also have to do the circuit board if your mechanic noted a fault in your 00 cluster.

 

[TheDurk]

I had the cluster out the other day doing an LED swap. Can anyone point me in the correct direction as to where the circuitry is for the gas gauge?

My brother is an electrical engineer and he said the board on the back looked especially clean...

Toyota gives us very good circuit diagrams for connecting one thing to another. They tell us very little about what goes on within the various things. All you can do is look at where the fuel gauge is soldered in and where the sending connections come in and try to follow the traces between the two.

Fuel signals come in on Pins 4,5 and 6 on Plug C28, which is a blue plug with 12 pins.