I have a new to me 55 fairlane. It has been rewired with 12 volt system. The fuel gauge is not moving off the below empty resting place. It is suppose to have a new sending unit.It registers 33 oms. The wire coming from the fuel gauge to the sending unit is 2.1 volts..All measures with a known good ground. and taken at the sending unit. I have not tried to get to the back of the fuel gauge itself . Car had aftermarket wiring harness and ac so under dash is very full. I ran a wire from battery directly to the wire from sending unit to gauge and dash gauge didn't move. Any suggestions? I don't know if they installed a voltage reducer or not. Prior owner said the gauge worked for a while but the intermittently worked and finally stopped. I'm thinking by the ohms reading he installed a 56 sending unit instead of the 55. Not sure if I found the issue or not but there is a voltage reducer mounted on the back of the fuel gauge.I managed to get the cluster removed and after I stopped bleeding from reaching under the dash and removing nuts lol I found the voltage reducer wasn't working. I had 12 volts input and no output. I quickly attached the hot incoming to the gauge post and it started to move. Will not know if cured until I can get another voltage reducer.
The one in the car is like this. I am not getting voltage through it and no continuity with ohm meter. I'm concerned with the ohms on the sending unit. It seems a lot higher than the specs for the 55. I'm wondering since it's converted to 12 volts if they didn't replace the 55 sending unit with a 12v one from a 56. If so i don't know if it will work or not https://www.speedwaymotors.com/Spee...xKcE9u0s1RQWqTGex82dgR0zK6PdJbS2lqZ56J0If4ruU
Look at the you tube video post (the one below yours) and there is a lot of information you could use. Dan is very knowledgeable about 55 Fords.
Earluy Fords used King -Seely gauges, that Runtz unit won't work, when Ford went back to using 6 volt gauges in 1957 they used the one I posted in the link above. This shows how it is wired in a Mustang. Shown as the constant voltage unit.
Thanks for the info. The new reducer came in today and got it wired in and now fuel gauge is showing 1/4 tank NO idea how much fuel is in tank but at least the gauge is moving
Here is how I calibrated my fuel gauge and sender....Drain the tank. Remove the sender from the top of the tank. Pour in 7.3 gallons of gas through the sender opening ( 1/2 of the 14.6 gallon capacity). Reinstall the sender with a couple of screws. Turn on the ignition. The gauge should read exactly 1/2 full. If the reading is off then just slightly bend the wire arm on the sender either up or down depending on the gauge reading. Repeat process until the correct 1/2 reading is achieved.
This may be of some help https://www.tanksinc.com/index.cfm/page/ptype=results/category_id=159/mode=cat/cat159.htm
Thanks for the help and suggestions. Replaced the voltage regulator and gauge worked. I siphoned out as much fuel as possible and gauge went below empty. Put in 7 gal and showed just below 1/2 so good to go. Now onto rebuilding the door hinges and several other chores.
The Jalopy Journal
