Fuel gauge issues
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New User
Joined: Jul 2020
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Fuel gauge issues
Since I bought my 89 C-8000 the fuel gauge has never worked. I did some tests and checked some wires and connections and everything seemed to be ok. I pulled the sending unit out of the tank and began to move it manually to see what happened at the gauge. When I pull the float up, the gauge registers empty. When I pull the float down the gauge registers full (backwards). I tried switching the wires on the sending unit and nothing changed. I verified the float floats. Even when the tank has been empty in the past the gauge has never moved. When I check the resistance at the sending unit, I have the highest resistance when the float is in the empty position. Sending unit is marked D4HF-9275-AA. Any thoughts?
Fleet Mechanic
Joined: Feb 2007
Posts: 1,652
Likes: 79
From: Mooresville, NC
If the Rotunda/Ford test gear is not available, the shop manuals typically say use a 73 ohm resistor to check the LOW (band) and a 10 ohm resistor to check the HIGH (band).
It appears (I'm not there to take measurements) you might have a problem with the IVR -- Instrument Voltage Regulator that is designed to keep a constant 5V at the instrument gauge / on that fuel level indicator. If the Voltage (V) reference level / floor is wrong, the sender can be sending the right signals and the gauge would still read incorrectly
It appears (I'm not there to take measurements) you might have a problem with the IVR -- Instrument Voltage Regulator that is designed to keep a constant 5V at the instrument gauge / on that fuel level indicator. If the Voltage (V) reference level / floor is wrong, the sender can be sending the right signals and the gauge would still read incorrectly
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 787
From: Simi Valley, CA
If the Rotunda/Ford test gear is not available, the shop manuals typically say use a 73 ohm resistor to check the LOW (band) and a 10 ohm resistor to check the HIGH (band).
It appears (I'm not there to take measurements) you might have a problem with the IVR -- Instrument Voltage Regulator that is designed to keep a constant 5V at the instrument gauge / on that fuel level indicator. If the Voltage (V) reference level / floor is wrong, the sender can be sending the right signals and the gauge would still read incorrectly.
It appears (I'm not there to take measurements) you might have a problem with the IVR -- Instrument Voltage Regulator that is designed to keep a constant 5V at the instrument gauge / on that fuel level indicator. If the Voltage (V) reference level / floor is wrong, the sender can be sending the right signals and the gauge would still read incorrectly.
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