I have a 1990 Ford 460, Dolphin, Class A and I just replaced the Fuel Sender and Float and gas guage sticks on full. I have 1/3 of gas in tank, Tank is a 75 gallon, part I bought is a Motorcraft Fuel Pump/Sender with Float, Instructions for installation came with it and me and my RV mechanic installed it this last weekend. I know we installed it correctly because the Generator works and the Coach runs, but the gas guage appears to be stuck in the FULL position.
I know the part is correct because I have researched this part for months and it does cross check from the old original one.
Any advise would be Greatly Appreciated and Thank You in Advance
An open circuit between the fuel gauge and tank will cause a EMPTY reading, and a shorted circuit will cause a FULL reading. Simply stated it is a potentialometer and volt meter circuit. (Resistor and amp-meter.)
Check grounds and wiring connections. Use a ohm meter to check the sending unit, it should show low ohms, about 10 to 15 for the amount of gas you have. Use a tail light bulb to ground the wire from the gauge to check the gauge. It will read empty. Use the bulb just in case you get across the feed to the electric fuel pump. Good hunting.
I will try this tomorrow, however, your test with tail light bulb and gauge is a little confusing, Sorry, not a electric person.
I will purchase a ohm meter tomorrow at Radio Shack and maybe my RV mechanic will understand this procedure that I have copied what you wrote.
I do not agree with the information you are being given here by Tek-Rep.
I had told you previously that grounding the fuel level sending wire will cause the dash gauge to show full and disconnecting that same wire will cause the dash gauge to show empty and you stated that it worked that way.
The information you stated on this RV site is that the dash gauge sticks on full. (The needle should drop to empty when the switch is off and if it doesn't, the dash gauge may be stuck or defective). If the needle shows empty with the switch off and full with switch on, that tells me you may have connected the wrong wires when you installed the new style 4-wire jumper onto the original 3-wire harness. I hope that you prove me wrong because that may require lowering the fuel tank again. to correct the jumper harness connections.
1995 Ford F53 Bounder 35U
Cold Spring Minnesota