2010 where to find fuel sending unit wire under dash; colors?

[Viper Driver]

Inherited my Dad's 2010 limited. V6. Fuel gage consistently reads low. Have spent tons of time looking online for where I can find the wires that run from the fuel sending unit in the gas tank to the instrument cluster. I'm trying to avoid dropping the tank and/or getting to the C434 connector location basically on top of the tank where the wires come out. My 85% belief after researching is the wire colors coming out of an OEM pump/sending unit are Yellow/White and Black/Orange. I would expect to find those colors at the connector on the back of the instrument cluster, but don't, so either those aren't the right colors or the sending unit gets run through some other location for "processing" before heading to the instrument gage. Supposedly there is a connector with these 2 wires in it located in either the passenger side or drivers side foot kick panel. Looked both places and no luck. Any info, especially with pix would really help. My plan is to get a variable resistor pot to put in the line to see if that'll fix the issue. No codes. Everything acts like it should except it's all about 4-5 gallons low on the gage than what's in the tank. The flow meter that calculates gallons used seems to be quite accurate when compared to fill ups. As an example, when my gallons used meter shows 15.6 gallons used, the fill up is 16.2 gallons, gage needle is solidly in the middle of the "E", and the computer shows zero "0" miles until empty with the fuel low warning on. At completely full via top off at the gas station, the needle will get to roughly 7/8.

I have also not found what gives me much confidence in which direction the sending unit works; i.e. empty is a low ohm reading or high with full being opposite. I'm assuming for purposes of what I want to try, is full is the high number. If I can find the right sending unit wires under the dash, I plan to install a simple and cheap 100 ohm variable resistance pot and go from there. Worst case, I should be able to leave it on zero and still use what I have been. Also have read a bunch of high level info written by what appear to be electrical engineers on all the "what if" pieces of doing what I plan, with all of the outcomes bad. I'm going for something simple. If the gage is looking for 180 ohms full but is only seeing say 160 for whatever reason, if I put a pot in the line (series) to give it another 20 ohms, maybe it's a win? Or maybe I fry the entire instrument cluster...

 

[J_C]

Try to find a wiring diagram. There are a couple online sites linked in 2nd line of my sig below.

This might be it:

Fuel Pump Wiring Diagram

Hi all, I'm posting for my other half that has no internet access at the moment, so bear with me please. His question/request - "I need a diagram of fuel pump wiring, specific to the 2006 Ford Explorer. What terminals do I need to jump straight to the batter power to bypass and check the fuel...

www.explorerforum.com

As far as the wire colors changing, I'd check for bulk connectors under the hood, near the firewall, maybe that's where the run from the pump sending unit ends, at that connector.

I'm thinking you might not find it as easy as just rigging up a variable resistor, that the gauge is always going to be off... but I could be wrong.

One thing I would try is a fuel system cleaner that is designed to also clean the sending unit resistor, something like Techron Plus fuel system cleaner.

Since your gauge isn't sticking, the reading being off would tend to be from higher resistance, like if you have sulfur deposits on the sending unit resistive strip which is essentially a linear potentiometer. This would suggest that if it is reading lower than actual fuel level, that the resistance needs to be lower to mimic the actual fuel level reading.

 

[Viper Driver]

Try to find a wiring diagram. There are a couple online sites linked in 2nd line of my sig below.

This might be it:

Fuel Pump Wiring Diagram

Hi all, I'm posting for my other half that has no internet access at the moment, so bear with me please. His question/request - "I need a diagram of fuel pump wiring, specific to the 2006 Ford Explorer. What terminals do I need to jump straight to the batter power to bypass and check the fuel...

www.explorerforum.com

As far as the wire colors changing, I'd check for bulk connectors under the hood, near the firewall, maybe that's where the run from the pump sending unit ends, at that connector.

I'm thinking you might not find it as easy as just rigging up a variable resistor, that the gauge is always going to be off... but I could be wrong.

One thing I would try is a fuel system cleaner that is designed to also clean the sending unit resistor, something like Techron Plus fuel system cleaner.

Since your gauge isn't sticking, the reading being off would tend to be from higher resistance, like if you have sulfur deposits on the sending unit resistive strip which is essentially a linear potentiometer. This would suggest that if it is reading lower than actual fuel level, that the resistance needs to be lower to mimic the actual fuel level reading.

Thanks JC. Those links are nice. I've run many bottles of Tech + through it to no avail. Figured if I could find that Yellow/White sending unit wire and slap a pot on it, especially if it were under the hood and easy to get to, I'd go that route. I've reached that age where getting under the dash isn't the big one either. Since this was inherited, there are no maintenance records and that surprises me, but I think the pump may have been swapped out several years ago and it somewhat seems that's when Dad's fuel gage started reading wrong, but I'd only driven the vehicle once at that point for a short hop that didn't include refueling. I may visit the 2 shops where I think he may have had the work done to see if they have records, just to help me understand what may or may not have taken place.

I did look at the connectors under the hood, passenger side up near firewall where I'd expect that sending unit wire to show up possibly before being sent to the instrument cluster. No Yellow/white.

Thanks again for your speedy response and help.