low fuel indicator light access
Thread Starter
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Senior User
Joined: Feb 2003
Posts: 171
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From: Utah
low fuel indicator light access
I want to use the low fuel indicator light to trigger a timer to pump gas from a bed mounted tank to my main fuel tank. My idea is to simply trigger a timer or time delay relay when the low fuel indicator comes on. I'll set the timer to run the pump long enough to pump 20-25 gallons and then shut off. That way, as long as I keep fuel in my big tank, it'll always automatically pump it to the truck's main tank.
Does anyone know if there is a wire from the dash console that has that signal on it? Or, is that signal completely contained in the dash module?
Thanks,
John.l
Does anyone know if there is a wire from the dash console that has that signal on it? Or, is that signal completely contained in the dash module?
Thanks,
John.l
Elder User
Joined: Aug 2003
Posts: 568
Likes: 1
From: Kansas
Sounds kinda complicated, neat idea but what about a plan old under the dash mounted switch on a timer? Maybe someone else will have the answer for you. My low fuel light comes on sometime when I go around a corner or stop or start run quick. Kinda inconsistant with the actual meaning of "low fuel".
The switch deal would work real well if the fuel gauge would increase as fast as it was pumping it in...not one of Fords better ideas.
The switch deal would work real well if the fuel gauge would increase as fast as it was pumping it in...not one of Fords better ideas.
Fleet Owner
Joined: Jun 2004
Posts: 25,090
Likes: 1,112
From: Rio Rico, AZ.
Originally Posted by yellow73bb
I want to use the low fuel indicator light to trigger a timer to pump gas from a bed mounted tank to my main fuel tank. My idea is to simply trigger a timer or time delay relay when the low fuel indicator comes on. I'll set the timer to run the pump long enough to pump 20-25 gallons and then shut off. That way, as long as I keep fuel in my big tank, it'll always automatically pump it to the truck's main tank.
Does anyone know if there is a wire from the dash console that has that signal on it? Or, is that signal completely contained in the dash module?
Thanks,
John.l
Does anyone know if there is a wire from the dash console that has that signal on it? Or, is that signal completely contained in the dash module?
Thanks,
John.l
Posting Guru
Joined: Feb 2004
Posts: 2,248
Likes: 1
From: Elverson, PA
Just my thoughts - but if something were to go wrong - you could by trying to pump more fuel into an already full tank. I would think maybe a safer way, albeit maybe not nearly as cool, would be just to have a switch that you throw to make the transfer pump run in your auxillary tank.
Fleet Mechanic
Joined: Feb 2004
Posts: 1,816
Likes: 3
From: River Valley AR
If you could tie into the wiring that illuminates the low fuel light, that could turn on a relay very easily.
Tying in directly at the tank will depend on what trips the low fuel light on. It could be resistance, capacitance, normall open or normally closed.
If you were to use a timed light switch in the cab, you could use it to open a solenoid valve when your low fuel light came on. It would stay open longer the further you turned the switch. If you put two solenoid valves in series it would give you some protection if one valve should happen to stick open.
You could also use the solenoid valves with the relay I mentioned above, but I am not familiar enough with your truck to know where to tie it in. I know that there are industrial relays that have adjustable timers on them.
Then again there's always the tried and true toilet bowl fill valve....
Tying in directly at the tank will depend on what trips the low fuel light on. It could be resistance, capacitance, normall open or normally closed.
If you were to use a timed light switch in the cab, you could use it to open a solenoid valve when your low fuel light came on. It would stay open longer the further you turned the switch. If you put two solenoid valves in series it would give you some protection if one valve should happen to stick open.
You could also use the solenoid valves with the relay I mentioned above, but I am not familiar enough with your truck to know where to tie it in. I know that there are industrial relays that have adjustable timers on them.
Then again there's always the tried and true toilet bowl fill valve....
Thread Starter
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Senior User
Joined: Feb 2003
Posts: 171
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From: Utah
The timer is pretty easy to build. I probably wouldn't use a time delay relay because of the cost. I'd just use a simple electronic circuit (7555 timer or something). I looked at my Haynes manual, but can't find the low fuel light anywhere in the schematics. The schematic shows a dashboard microcontroller, and I presume it controls the light. If I can't find easy access to the low fuel light, I'll do the toilet valve. The electronic equivalent of the toilet valve is a simple op-amp comparator with lots of hysteresis. Just have it turn on the pump when the level gets down to 1/4 tank and turn off when it gets up to 3/4 tank or something like that. Could also have a fail-safe timer I guess.
I already have a simple dash mounted switch, I'm just looking for something a little more automated, and something that won't overfill. I can trust electronics to shut off the pump, I probably can't trust myself to remember to shut off the switch every time before it overfills.
I already have a simple dash mounted switch, I'm just looking for something a little more automated, and something that won't overfill. I can trust electronics to shut off the pump, I probably can't trust myself to remember to shut off the switch every time before it overfills.
