Most 2013 and some 2014 NO fuel heater engaged

[cerberusiam]

Fuel doesn't gell in the tank as the mass of fuel will retain the heat. Gelling in the tank would happen at the edges but the return lines pump about 75% of the fuel sent the fuel system back into the tank thru the cannister os it rarely if ever gells at the pickup. The gelling happens in the filters and lines that are fully exposed all the way around to the cold. In these cold temps just a lack of a winter front will gell the fuel in the OE cannister without a heater. The rear filter is even worse because it has protection from the cold, it needs the heater worse than the other one.

 

[AH64ID]

The other morning it was 16° out, my fuel filter had a temp of 16.5° on the bottom of it (Fluke IR thermometer). I went for a drive to get my folks at the airport, about 20 minutes. When I got to the waiting lot the bottom of the filter was 43°. This is my filter that is mounted back by the transfercase. I do have it wrapped in foam, and it has a fuel heater built in.

Between the two 300w heaters, the foam, and the heat from the returned fuel it warmed up quite a bit in a very short amount of time, I was impressed.

 

[crabjoe]

On CF, it was posted that the TSB for this is tsb 14-005-13. Does anyone have it, to post?

Thanks!

 

[Dieselnerd]

On CF, it was posted that the TSB for this is tsb 14-005-13. Does anyone have it, to post?

Thanks!

Yes, I'd like to see it too and be able to print it out to take to my dealer.

I did some searches but came up empty.

 

[RikDavis]

I think I can ad mine to the ones with this problem. Checked both filters this morning with IR thermometer. both at 7 degrees. Left key on for 15 minutes. Engine mounted filter at 35 degrees, no change on the rear frame mounted filter

 

[gsbrockman]

Validate proper heater operation by testing for battery voltage at the heater connections with the
ignition switch is in the Run position.

As asked previously....two questions :
1) What voltage should I be seeing at this connector if disconnected at the heater???
2) Is there a minimum ambient air temperature required for the fuel heater to engage???

Thanks for all of your contributions to the forum...

 

[sag2]

As asked previously....two questions :
1) What voltage should I be seeing at this connector if disconnected at the heater???
2) Is there a minimum ambient air temperature required for the fuel heater to engage???

Thanks for all of your contributions to the forum...

The heater assembly is equipped with a built-in fuel temperature sensor (thermostat) that senses fuel temperature. When fuel temperature drops below 32° F (0° C), the sensor allows current to flow to built-in heater element to warm fuel. When fuel temperature rises above 64° F (18° C), the sensor stops current flow to heater element (circuit is open).

Voltage to operate fuel heater element is supplied from ignition switch, through "relay in the PDC", to fuel temperature sensor and on to fuel heater element.

The heater element operates on 12 volts, 300 watts at 0 °F (-18° C). As temperature increases, power requirements decrease.

A minimum of 7 volts is required to operate the fuel heater. The resistance value of the heater element is less than 1 ohm (cold) and up to 1000 ohms warm.

 

[TimothyLong]

The heater assembly is equipped with a built-in fuel temperature sensor (thermostat) that senses fuel temperature. When fuel temperature drops below 32° F (0° C), the sensor allows current to flow to built-in heater element to warm fuel. When fuel temperature rises above 64° F (18° C), the sensor stops current flow to heater element (circuit is open).

Voltage to operate fuel heater element is supplied from ignition switch, through "relay in the PDC", to fuel temperature sensor and on to fuel heater element.

The heater element operates on 12 volts, 300 watts at 0 °F (-18° C). As temperature increases, power requirements decrease.

A minimum of 7 volts is required to operate the fuel heater. The resistance value of the heater element is less than 1 ohm (cold) and up to 1000 ohms warm.

Thanks for posting this info!

 

[gsbrockman]

So....if I'm reading this correctly....there's about 12V at the heater connector constantly as long as the key is in the run position, but the heater itself will only engage if the fuel temperature is =< 32*F and will shut off if fuel temperatures are => 64*F.

 

[sag2]

No, voltage will only be present when heater is commanded on by temperature.

 

[AH64ID]

No, voltage will only be present when heater is commanded on by temperature.

The 4th gen may be different than my 3rd gen filter on the frame, but the voltage is always present at the heater and the thermostat is internal to the heater.

 

[gsbrockman]

No, voltage will only be present when heater is commanded on by temperature.

My dealer supposedly did this flash Saturday. On Tuesday, I high-idled / warmed the truck up for about 9 minutes, and test drove for 4 miles. Prior to leaving (ambient temps were 9*F by the way) I checked the connector for voltage....zero point zero...just like Blutarsky's GPA from Animal House. Filter base and filter never got warm to the touch. I take my truck back yesterday.....and they finally got it turned on. I went out this morning (26*F) and turned the key to RUN. I had 12.43 volts at the connector. I'm going to say that I respectfully disagree with you; if the heater operation is not determined by ambient air temps (you stated heater operation is determined by fuel temps and the thermostat within the filter base) then the thermostat and heating element will need a 12V "RUN" source so that the thermostat can determine if operation is needed or not.

 

[RikDavis]

Now that you know it is turned on it would be interesting to know if the voltage remains there in warm weather or goes off from some kind of sensor the computer is reading.
I am taking mine in monday morning. We will see what happens.
We have good temperature forecasts for the next few days so I imagine you do too

 

[gsbrockman]

Now that you know it is turned on it would be interesting to know if the voltage remains there in warm weather or goes off from some kind of sensor the computer is reading.
I am taking mine in monday morning. We will see what happens.
We have good temperature forecasts for the next few days so I imagine you do too

I'm gonna bet there will be ~ 12V there 100% of the time....as long as the software is "SET" and the key is in the "RUN" position. I really feel the filter head will need 12V all the time.....and the thermostat within makes the call if the heater element is engaged....and to what amount of wattage.

It's easy enough for me to check.....perhaps I will.

 

[Kirwin]

I suspect you are right Mr. Brockman. The fuel heater relay is not controlled by the PCM. Thus I suspect it is just another circuit that is supplied from the run side of the ignition switch. I also think, as you do, that the fuel heater is supplied 12 volts when ever the truck is on and the thermistor built into the circuit has a very high resistance above 64 F and turns on (has a very low resistance) below 32 F and thus it is the component that determines when the heater is active. At first I thought they has just spliced the relay output wire and that the under body fuel heater was supplied from the same relay since there are not two fuel heater relays in the PDC, however, this doesn't make sense as some on here report that the engine heater is working before the reconfiguration and that both are working after reconfiguration. This leads me to believe that the fuel heater relay may energize the engine mounted filter heater circuit and may trigger the BCM to act as a relay and supply 12 volts to only the under body mounted fuel filter heater thermistor circuit through the BCM. I suppose that the relay may be controlled like the fuel pump and the relay may not close until the engine is actually running to preserve battery power in case you turn the truck to the on position and do not start the engine. It would be nice if we could get ahold of the actual wiring diagram to see how it really works and then we could stop guessing. I think I will take some readings as I haven't taken mine into the dealer to get it reconfigured yet. None of this really conflicts with what Sag2 has posted from the training manual. It's just another way of reading what he states. It is interesting to note that a 300 watt heater would draw 25 Amps at 12 volts. That is out of the range of most "electronic modules" to supply and would normally be a hard wired relay supplied load. Ken Irwin

 

[gsbrockman]

I took some pictures just this morning...
This is the pic of the 12V source for the rear frame mounted filter.
#ad


Turn your truck to the "RUN" position, disconnect the connector, and check for ~12V utilizing the connector on the left (the other end goes to filter head) There's only two wires in this connector...simply use the positive and negative probes from your multi-meter to touch both metal tabs in the connector. At 26*F this morning, mine showed 12.43 volts. If it's truly enabled, I believe you should find ~ 12V here at any ambient air temperature.
#ad


Kirwin....I know it's hard to tell by looking at the pics, and I'm no wiring guru, but the gauge wire I'm seeing is probably on the light side for a 25 amp 12V source....what's your thoughts???

 

[Kirwin]

After studying both my trucks Power Distribution Center (PDC), and my DVD service manual, and further scratching around on the web, I found a wiring diagram by accident on tech authority. From the 2014 D2 trucks wiring diagram, fuse 9 (40 amp) supplies the engine mounted fuel filter heater directly from the diesel fuel heater relay (K 9?) which gets control power from the run/start relay and is grounded by G104. Thus effectively it is energized all the time the ignition is in run/start as we thought. The heater wire color codes are pink with dark green tracer supply with a black ground. The chassis fuel filter heater is supplied from fuse 37 (30 amp) from fuel heater relay #2 with the control power source being pin 12 of the body control module (BCM) and the relay grounded at G 105. The heater wire color codes for this circuit are pink with light blue tracer and a black ground. So this answers most of the questions. The BCM obviously knows what the ambient temperature is, so I'm going to check my before and after readings at the chassis fuel filter heater connector and see if it is indeed on all the time or if the BCM does actually cycle it based on its perceived fuel (ambient) temperature. It still seems to me to make sense that the BCM would supply power to the chassis mounted filter heater relay circuit at all times and the thermistor would allow current flow to maintain fuel temperature in band based on fuel temperature at the filter head. Mr. Brockman I concur that the wires running to and from the chassis mounted fuel filter are too small to carry 25 amps. Thus I'm guessing that this heater is rated at a lower power output and hence has a smaller fuse protecting it. Ken Irwin

 

[Kirwin]

So, after I found the wiring diagram last night I did some more research and with a clearer head this morning I delved into this deeper. The fuses and relays listed on the underside of the Power Distribution Center (PDC) cover is generic. Relay K-13 is listed on the cover as a spare but is in fact the relay for fuel heater #2. This is backed up by the wiring schematic stating that circuit controlled is F327 which equates to the pink with light blue tracer wire in Mr. Brockman's photo above and confirmed on my truck to be the correct color code for this circuit. Thus fuel heater #2 is the chassis mounted fuel filter heater. So the heater power flow is as follows: from the run/start bus in the PDC, to relay K-13, then through fuse F-37 to the chassis wiring harness that runs down the passengers side frame rail (which also includes the the transmission wiring, and exhaust after treatment wiring) to the frame mounted fuel filter assembly. Control power for K-13 comes from the Body Control Module (BCM) circuit K-37 (which is pin 12) and the relay is grounded via a common ground for the PDC on circuit G-105.
For the engine mounted fuel filter heater, relay K-09 is also listed as a spare on the underside of the PDC cover but is fuel heater relay #1. This relay receives power from the run/start bus in the PDC, then through fuse 9, and then connects to the fuel heater connector (D6657A) through the engine wire harness (connector C-3, pin 22) via circuit F-326 which is 12 Ga wire and can handle the 25 amps for the primary fuel heater with no problem. This is the circuit that you can see at the fuel filter heater connector with the red and black wires showing on the engine mounted fuel filter assembly. Ground for the heater circuit is provided by G-916A. Control power for relay K-09 comes from the run/start bus in the PDC and ground is provided by G-104 which appears to be another PDC common ground. Thus anytime the run/start relay is energized in the PDC the engine mounted fuel heater has 12 volt power available and is only controlled by the thermistor that is in the fuel filter head integral to the heater circuit. The chassis mounted fuel filter relay K-13 must be supplied power from the BCM and this must be what reconfiguration of this module does. I.E. it enables the 12 volt output from the BCM to relay K-13, hence no chassis mounted fuel heater unless you have had the reconfiguration completed, but the engine mounted one works. Ken Irwin

 

[sag2]

View attachment 2013 diesel fuel delivery.pdf

View attachment 2013 engine mounted fuel heater operation.pdf

Kirwin, very nice job explaining it. This should help everyone so they can better understand the system.

 

[EHarold]

TCDiesel, THank you for this valuable information. I had the truck towed 3 times for gelled fuel. The manager was getting a little short with me. -18 will do that if this thing isn't configured correctly. Now the question is do I go back on Monday and discuss why they kept telling me it was bad fuel and do they need to change the filters now that it has gelled 3 times?

Thank you again. The post was helpful.