Broncosaurus!
New member
both my chilton and haynes manual conveniently leave out all mention of the fuel gauge and sending unit. How do I test the sending unit and do I have to drop the tank to change it?
fuel gauge trouble shooting? How do I do it, where do I start
- Thread starter Broncosaurus!
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Seabronc
New member
If you want to start by gaining access to the sender unit without dropping the tank, you will have ot make an access hole. You can do that with the tank in place, done with fear and trembling, but doable http://broncozone.com/forums/index.php?showtopic=12329 or drop the tank. If you are flexible enough, you may be able to reach up from underneath the truck and remove the connector for testing. The problem could be a bad connection, sender, wiring or gauge, but rarely the gauge. I had to run a new ground from my ground distribution bus to the sender connector in order to get reliable readings on the gauge.
You can do a quick check by disconnecting the connector from the sender. Measure the voltage on the yellow with white stripe lead, one probe on the contact and the other running to a good battery ground, NOT the frame or chassis. You should see about 5 volts. Then do a continuity check on the black lead to battery ground, it should be virtually "0". If that is OK, check the gauge reading with the connector off (empty), and then check it with the two pins of the connector shorted together (full). If you can get a 22 ohm and a 73 ohm resistor, then the 22 ohm one from the yellow lead to battery ground will indicate 1/2 full and a 73 ohm resistor will read right on E. If those readings are OK, replace the sender, your choice on how to do it.
Good luck,
>-I have eliminated, as much as possible , using the chassis and body for grounding. It only has 1/10 th the conductivity of copper.
OP
OP
Broncosaurus!
New member
OK good info, I like the write up, can I get to the sending unit plug from the bottom of the truck? Or where is the plug? So that is a big conglomerate of ground wires there? And one big wire goes to the neg on the battery?
