Author Topic: Low Fuel Sending Unit  (Read 2471 times)

Offline orgnl70

  • Jr. Member
  • **
  • Posts: 56
Low Fuel Sending Unit
« on: August 25, 2012, 09:50:36 AM »
Has anyone have a line on restoration of a low fuel  sending unit? Thank you

Offline ruppstang

  • Hero Member
  • *****
  • Posts: 3936
Re: Low Fuel Sending Unit
« Reply #1 on: August 25, 2012, 10:17:23 AM »
I repaired the one in our 67 GTA. Most often the diode fails and it is just a matter of replacing it. NPD has them part #9A275-1  it is listed as a 67-68 part. I have not worked on the latter models and do not know if this part will work for them. You did not say what year you are working on. Does your fuel gage read properly? This will only fix the low fuel light. Marty

Offline midlife

  • Wiring Guru---let me check your shorts!
  • Global Moderator
  • Hero Member
  • ****
  • Posts: 2174
    • Midlife Harness Restorations
Re: Low Fuel Sending Unit
« Reply #2 on: August 25, 2012, 10:08:10 PM »
Diode?  Don't you mean the thermistor in the fuel tank?  It's a device that changes resistance when saturated and dry.
Midlife Harness Restorations - http://midlifeharness.com

Offline ruppstang

  • Hero Member
  • *****
  • Posts: 3936
Re: Low Fuel Sending Unit
« Reply #3 on: August 26, 2012, 12:20:35 AM »
Yes Randy you are so right. I so not use those terms every day in home building :)

Offline midlife

  • Wiring Guru---let me check your shorts!
  • Global Moderator
  • Hero Member
  • ****
  • Posts: 2174
    • Midlife Harness Restorations
Re: Low Fuel Sending Unit
« Reply #4 on: August 26, 2012, 10:42:48 PM »
I don't think diodes were even invented or manufactured in 1967/68! 

Updated: Google says they were availabe in the 40's!
Midlife Harness Restorations - http://midlifeharness.com

Offline jwc66k

  • Hero Member
  • *****
  • Posts: 7346
Re: Low Fuel Sending Unit
« Reply #5 on: August 26, 2012, 11:38:49 PM »
Diodes date from about 1890-1900 although they're not the same as what is used today. The "sensor", aka thermistor, used in the low fuel circuit provides a direct electrical path when not immersed in a liquid thereby providing an electrical path to actuate the relay to provide voltage to the warning light. That means it shorts when there's no gas (or the other way around).
Jim
I promise to be politically correct in all my posts to keep the BBBB from vociferating.