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Help with fuel gauge

22K views 53 replies 5 participants last post by  antjciulla  
#1 ·
I’ve searched around and can’t seem to find anything I’m experiencing. My 2006 f250 fuel gauge always reads empty. Like below the red line even after a fillup. I was suspecting the fuel sending unit had gone bad from sitting before I bought the truck, but I finally got ahold of a multimeter and checked the resistance on a 200ohm scale of the actual sending unit and I’m getting 124 ohms of resistance. This number sounds about right since I filled up about 70 miles ago and the full tank ohm is 180. So do I have a wiring issue between the tank and the gauge or what should I check for. I appreciate any help.
 
#2 ·
possible it is the gauge
when you key on does the gauge move at all?
tap your finger on the glass on front of the gauge -- does it move?
the glass sits real close and sometimes the needles will bind up on the glass
if this is the case a "gentle" push/tap will sometimes push the needle farther onto the gauge stem and free it

can also put the instrument cluster into self test and force gauge movement to full stroke
 
owns 2006 Ford F250 Lariat FX4
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#4 ·
Not sure where you're reading it from, but here are some 2004 wiring diagrams: Hi-res Single Page 6.0L Wiring Diagram PDFs

If its possible to do the reading from the instrument cluster connector and it reads good, Circuit Board Medics has recovers an instrument cluster at reasonable prices.

The only thing I can say is just trace the wiring diagrams and maybe you'll see a relay the signal goes through or a point to check.
 
#5 ·
Not sure where you're reading it from, but here are some 2004 wiring diagrams: Hi-res Single Page 6.0L Wiring Diagram PDFs

If its possible to do the reading from the instrument cluster connector and it reads good, Circuit Board Medics has recovers an instrument cluster at reasonable prices.

The only thing I can say is just trace the wiring diagrams and maybe you'll see a relay the signal goes through or a point to check.
I have a spliced wire run from the sending unit into the cab and the ground attached to the frame. In the morning I’ll pull the cluster and see if I can bypass the original and get it to work. If so I’ll clean it up. Honestly I’m just glad it’s not the $300 sending unit like I thought it was the last year. I bought the truck last November and the gauge hasn’t worked since I bought it.
 
#6 ·
For further context, when I bought the truck there were wires cut behind the fuse box (not the upfitter switches, because I’ve already done the high idle mod), and it had this weird button with a red led screwed to the kick panel that covers the fuse box and stuff. Now that I’ve been tracing that damn yellow wire with the white line I see it’s cut down there I just can’t find where it leads to. Before today I didn’t know that was the sending unit signal wire.
 
#7 ·
I guess those wiring diagrams I linked are not the detail I thought. I had a copy on CD of the wiring diagram for my truck that included wire colors, posts, connectors with pin numbers, fusible links, and references to whatever the next page of the connection. Also included what I refer to as the mystery relays on the under the dash that do sit in the fuse boxes, but unfortunately that CD stopped working.

A 2006 wiring diagram in that detail would be perfect for what you're looking for. Unfortunately, these wiring diagrams are quite pricey.
 
#8 ·
Sadly they are so I’m not all to sure what’s been cut / spliced down there. Everything functions pretty good so I don’t think anything important outside of the sending unit wire. It’s a pesky thing because apparently it jumps through a bunch of different harnesses to make it’s way up to the cluster.
 
#9 ·
Still not working. Reran the wire to the pcm and I’m getting a good reading of resistance there. There are no frayed wires out of the loom that goes up to the cluster. I tried grounding it to the frame. At this point I’m so confused. I can go into gauge diagnostics and the gauge will sweep properly but it’s just not displaying the fuel level. Currently I can read the resistance at around 100 ohms. Everytime I drive it goes down so I know it’s working properly. All my other gauges works so I’m so confused.
 
#10 ·
Im confused -- why are you looking at the PCM for the fuel sender wire?
 
owns 2006 Ford F250 Lariat FX4
#12 · (Edited)
the wire does go in the main truck harness, but it does not stop at the PCM -- it continues up to the instrument cluster
are you looking at a diagram for the '06?

should be looking for a Black/Orange and Yellow/White at the instrument cluster
 
owns 2006 Ford F250 Lariat FX4
#13 ·
the wire does go in the main truck harness, but it does not stop at the PCM -- it continues up to the instrument cluster
are you looking at a diagram for the '06?
yes. It may just be the connected that’s right next to the pcm. It comes up the loom, connects to another loom and enters the main harness. Either way it doesn’t work when it’s directly connected to the cluster so I’m not sure what to do from here.
 
#14 ·
The diagram I have is from a 2004, the instrument cluster has three connectors, whereas the 2006 has two connectors -- the wire colors may be the same though
you are looking for a Black with Orange and a Yellow with White
 
owns 2006 Ford F250 Lariat FX4
#16 ·
the fuel gauge is on a regulated circuit, so the instrument cluster provides both hot and ground
looks like the black and the yellow are next to each other in the connector at the instrument cluster
I would check continuity of the wires from the cluster to the sender -- also for connection to frame ground, as this would affect the gauge

a resistor across the terminals/wires of somewhere between 70 and 200 would activate the gauge
you could use a potentiometer or a dash light bulb would possibly work, if you do not have a dedicated resistor
 
owns 2006 Ford F250 Lariat FX4
#17 ·
Here is a snippet of the '04 diagram

 
owns 2006 Ford F250 Lariat FX4
#19 ·
Cluster is not that hard if you take the dash part completely off
tilt the cluster out at the top and remove the connectors -- yes it will tilt
the remove the shift indicator

you can then reconnect the cluster with it laying out on the steering column
 
owns 2006 Ford F250 Lariat FX4
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#21 ·
#22 ·
#23 ·
Alright I have both (black with orange stripe and yellow with white stripe) directly connected to the back of the cluster and I’m still not getting anything. For resistance I’m getting 94 ohms which is average because everyday I check it after I drive it goes down. When the engine is running I get 4.6v at the connectors. What gives?
 
#25 ·
The gauge will sweep in test mode, check
the sending unit is within the correct ohm range, check
= the anti slosh circuit is not working
you will need to send the instrument cluster out for repair
in my opinion
 
owns 2006 Ford F250 Lariat FX4
#27 ·
Not that I know
it is the only other circuitry between the gauge and the sender
so by that, I think there is the problem

the gauge is actually a stepper motor, not like the old time gauges
that part of the circuit is working via the test mode

there is one more trouble spot, but it means opening up the cluster
the terminal pin connections on the harness connectors
can break the solder joints on the board
a simple re-flow of the solder is the fix
but unless you are able to solder and have a small iron
I would leave it up to the pros
 
owns 2006 Ford F250 Lariat FX4
#28 ·
Here is an example

 
owns 2006 Ford F250 Lariat FX4
#30 ·
Had the same thing happen in September. Was my Cluster. Sent it in to CBM and they fixed it. updgraded to LEDs with a new lense. It's like have a new truck!
 
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#32 ·
Circuit Board Medics can put the white background in if that is what you are wanting
I dont think you need to have it programmed, you would have the mileage from the previous life is all
 
owns 2006 Ford F250 Lariat FX4
#34 ·
Auto dim mirror and compass?
...well, I guess drivers side mirror as well
 
owns 2006 Ford F250 Lariat FX4