I've been doing google searches all day for the problem I'm having and I can't find any forum posts for exactly what I'm having problems with. My gas gauge has been all over the place for the past week or so. Sometimes when I start the truck it will read empty and then move to full as I'm driving when I have nowhere near a full tank. Then other times when I start the truck it will read 1/2 to 3/4 and slowly drift to full over the course of 10-15 minutes while I'm driving even when I don't have a full tank. Has anyone else had an issue like this?

 

2004 Ranger has a digital cluster(dash) called HEC(hybrid electronic cluster)

Google: Ford HEC dealer test mode

Watch a few videos on tests you can do

The fuel gauge still has an analog wire from sender in tank to the HEC, so not true digital
And the sender needs a good ground to read correctly
There is no "slosh module" in 2004 and up Rangers, that was a common failure in Ford gas gauges in previous years

Do the HEC tests and see what it shows
Next step will be to pull out the cluster and test the Yellow/white stripe wire on C220B pin 7
When unplugged from cluster it should show between 16 to 160 OHMs to ground
16 ohms EMPTY
160 ohms FULL
Then rock the truck and watch OHMs go up and down as sender's Float in the gas tank goes up and down from sloshing fuel
If OHMs are not stable, smooth up and down when rocking, then sender is most likely bad
If ohms check out then might be HEC issue, BUT.....................you need to match a new cluster to the computer, so need Ford Software to do that, which you can buy but might be easier to get Ford Dealer to do the swap

Engine can't be started with HEC unplugged or with unregistered HEC plugged in, just FYI, its part of the Anti-Theft system

 

I can’t get my cluster to go into hec test mode. Now the gas gauge is acting like it’s working properly. I’m wondering if maybe the connector at the tank is corroded or something to since every time the gauge acts up it lasts anywhere from a few minutes to about a week this time.

 

Sure thats possible, it is outside and can get wet
But you have to pull the bed off(or back) to get access to that 4 wire connector, just 6 bolts and 3 screws but still a pain to do

 

i need to pull my flatbed off here soon to do some work to it so I’ll inspect the connector on top of the tank when I do that. I’ll keep everything you said to try in mind if it keeps acting up. Thanks for going in depth with what all I need to check I appreciate it!