Today I did the following checks on my fuel gage: With the ignition switch on; Removed the 2 wire plug from tank, checked for voltage, none. Run a ground wire from bumper to each lead, no gage reading. Ran a jumper wire to both leads in the plug, no gage reading. Did an ohms test on the two leads coming from the tank, no reading. Replaced all 5 fuses in the fuse panel, no gage reading. I have about 5 gallons of fuel in the fuel cell. My guess is the gage but I hate to take the dash out, it could be a bear on these old models. I do not have a spare fuel gage nor a tank sending unit HELP! All ideas or suggestions welcome. Texasjack
With the ignition on...one of the wires should supply 12V at the tank plug. It must be broken between the plug and the fuse. You can run a temporary 12v jumper back and connect into the gauge wire and the gauge should jump to full if it is working. If the gauge works...start tracing the power supply back through the harness. Cleaver
Fuel Gage Inop Cleaver I did not know but there was no voltage. I will check that out. Thanks a lot. Texasjack
The constant voltage regulator only supplies 5 volts to the gauge. That goes through the gauge and then to the sender. If you apply 12 volts to the sender it will probably cause an explosion in the gas tank when the resistor in the sender unit burns up. Check the gauge to see if it is getting 5 volts (or pulsed 12 volts from the constant voltage regulator. If there is no volts to the gauge then replace the regulator.
75 Fuel Gage Inop Paul S Thank you very much. I pulled the dash panel and checked the voltage regulator and It had some weird readings. That is when I remembered I had a 73 F-150 insturment panel in my shop. It mounted upside down but as soon as it was installed the fuel gage started working. Getting the dash out was a real bear. The speedo cable would not disengage from the speedo head. The nylon clamp was loose and we tried pliers and vicegrips it still would not budge. My son jacked the car up and disconnected the speedo cable loose from the tranny and pushed the cable up. The only way that the instrument panel was going to come out. I remembered someone on the forum complaining about the dash lights being dim. I had the same problem on a VW Rabbit Truck. The VW and the Mavrick have a green plastic filter over the dash bulbs, so when we had the dash out we punched out the plastic filter and now the dash lights are as bright as a modern car. Paul S you saved the day. Thanks Texasjack This is a GREAT forum!!!!!!!!!!!!!!!!!
Fuel Gage inop Paul S It was your advise that saved me from chasing wires. I had enough wire chasing on the old model B-52s. Now that was an electrical nightmare. Thank you Texasjack
Chasing wires on a B-52 requires a skinny person and lots of "tunnel time". That has to be one of the "best" jobs in the Air Force. Glad I could help.
Good for you! By the way, Thanks for serving..... I appreciate the years you gave to help keep us free. Thank you.
Fuel Gage Paul S Thank you fo your service!! In June 1978 I retired form the Air Force. In June 2003 I retired from Lockheed Martin. Today I am going to look at the evaporator box to see what i need to do to remove that jewel. I hope you had a great Thanksgiving. Jack
