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Long story short my fuel gauge has never worked (pegged just past full), always assumed the sending unit was bad. Today after some reading I went to verify if the gauge actually works. That's when I discovered the plug that goes into the back seat to pass through was "rigged" back together and covered in electrical tape. Notice there is no female connector, the wires were just jammed in. I verified my gauge works using a paper clip watching my gauge go to empty. What I want to know is where I can find a connector to splice in, and where I can find a pinout of that connector so I wire it correctly while I'm under the car. As in, which pin is the ground, the signal (pink) and so on. Factory wiring diagrams don't show this connector as far as I found (I have the factory technicians manual).
The harness connector is Delphi 12020829. Or I guess it's the Aptiv brand now.
One wire is fuel pump +12V and another is fuel pump ground. You can probe the bulkhead connector on the body to figure out which wire is which:
* Find the ground wire by doing continuity check to chassis ground (key OFF so you don't accidentally ground a hot wire).
* The fuel pump power will go to +12V with key ON. Pull the fuel pump fuse and it won't.
The third wire is fuel sender +12V from the dash gauge pod. Ground that wire to chassis with key ON and your fuel gage will move to empty.
That connection/ or Connector is The C313 Electrical-Connector:
-Terminal "A" has a 16 AWG Black Wire, and is the 12V- (Ground) Connection.
-Terminal "B" has a 16 AWG Pink Wire, and is connecting the Fuel-Tank Float to the Fuel-Level Gauge.
-Terminal "C" has a 16 AWG Tan Wire, and is the 12V+ (Switched Power) Connection to power the Electric Fuel-Pump.
Below are two Schematics that show the C313 Electrical-Connector, and the Circuits that go through it:
The Connector that is missing, is available in Parts, to build yourself...
But I have NOT seen a Pigtail available for a long time.
You could try and purchase a used Pigtail from Members here, Forum Sponsors, or a Junk-Yard.
If you own the correct Delphi Terminal-Crimpers, let me know and I will Post the Part-Numbers...
so you can build a Connector for yourself.
So checked the pin out and got what the info needed with a slight catch. The power coming in, is only 8 volts. This is with key on engine off. So clearly a problem.
Whoops, should have specified that. Tan wire (looks white now from age) And to make sure I checked the wire inside the vehicle using a pin needle to get through the wire insulation.
Now, with that plug unplugged under the car I only get voltage from one of the terminals. And its 8 volts. I verified the ground terminal with an ohm meter. The 3rd terminal I assume would be for the fuel level gauge has zero voltage on the body terminal.
I have jumped the ground and the fuel gauge wire and watched the gauge move to E.
Now, with that plug unplugged under the car I only get voltage from one of the terminals. And its 8 volts.
Maybe it's all the cranberry juice talking tonight, but you should be getting full system voltage with no load (0 Amp current). Where are the two probes touching during this measurement?
I could maybe see getting 8V at the fuel sender wire because there's a leg in the gauge circuit that is pulling current even with the fuel sender disconnected. Essentially you'd be measuring voltage at the the center node of a 3 resistor wye.
Maybe it's all the cranberry juice talking tonight, but you should be getting full system voltage with no load (0 Amp current). Where are the two probes touching during this measurement?
One is directly in the the body harness plug, center terminal. The other probe using a gator attachment is hooked to a bolt on the frame for an exhaust hanger. I've checked multiple grounds just to make sure. Inside the vehicle I used a T-pin and punctured the tan wire to get a voltage reading, and used a body ground bolt for the ground. Same voltage, 8 volts. I'm extremely confused at this point.
Edit: I just had a thought, that power wire isn't going to be a constant 12 volts is it? Only when the key is turned on for the first couple seconds and the pump primed?
Last edited by Blue_Thunder; 09-07-2021 at 11:03 PM.
The Electrical Connector has three Terminal positions.
They are marked on the Electrical Connector body: A, B, C.
I told you what each Terminal position is for, in one of my Posts above.
Please reread the Post, and confirm which Wire that you are referring to.
The Electric Fuel Pump Relay and Electric Fuel Pump Switch, have a constant 12V+ connection via the Battery.
The Electric Fuel Pump does not have a constant 12V+ connection.
09-06-2021, 09:31 PM
Maybe it's all the cranberry juice talking tonight, but you should be getting full system voltage with no load (0 Amp current). Where are the two probes touching during this measurement?