I INSTALLED A NEW SENDING UNIT IN THE TANK AND CHECKED THE INSTRUMENT PANEL GAUGE AND IT CHECK TO BE GOOD BUT THE GAUGE DOES NOT READ ACCURATE. THE TRUCK HAS BEEN CHANGED OVER TO 12 VOLTS. CAN SOME HELP ME
KELLY

 

Is the guage in the dash a 12V? If not, you'll eventually fry it. I don't think it will handle the extra voltage. It was made to operate on 6 V. You may have to use a voltage drop or reducer to get it to work properly.

 

THANK YOU FOR RESPONDING , I WONDER HOW I WOULD DROP THE VOLTS.THE TRUCK HAS THE 6 VOLT GAUGE.
KELLY

 

Kelly,

Stop right now and go pull the battery out of your truck. If you are running 12 volts with no other type of regulator, you are begging for a fire. Now would also be a good time to check the overall condition of the wiring and replace any worn leads.

Check out this link to start, then go to you local mechanic or bookstore and get some more info.

https://www.ford-trucks.com/dcforum/48_60/984.html

Good luck!
Kris Taylor
Winnipeg, Canada
1950 F47 (For Sale)
1977 XS650
1997 F150XL

 

Both sender and gage have heater coils wrapped around bimetallic strips to heat/bend them. At the sender end, bending the strip interupts current flow via a set of points. (Point gap is varied by float position.) So more current at higher float levels causes higher gage reading. Heating coils are power devices. Higher voltage (12 vs. 6 volts) results in less current for same amount of power, the coil doesn't heat up as much and the gage reads low.

Remove the gage from dash, remove the two nuts and covers from the back exposing two 'gear-wheel'-type adjustments, one for empty the other for full. Remove sending unit, measure distance from flange to tank bottom (mine's 11"). Clamp flange edge of sender to a bench, bend float stop tabs to adjust float drop (bottom edge of float) to 11" for empty. Set top of float level with bottom edge of sender flange for full. Connect wiring (did mine with engine running to get about 14 volts) and adjust the gage at empty and full positions.

This worked for me with no other changes to the 6-volt hardware.

 

Try http://www.cgfordparts.com I had the same problem, and they have the voltage reducer for cheap. You just hook it up to the existing connectors on the back of your guage, and connect your wires to the reducer, real easy. Only problem, was the earlier owner fried the sending unit itself, and The bolts holding it on move, but dont unscrew. SO, i am back to square one, but with a voltage reducer. Ho- hum....