Auxilary fuel pump force on

[dutchofsc]

I have an 803a, I want to force the auxiliary fuel pump ON, even when the float switch is satisfied. I want to wire in a switch to make the aux pump turn on, to top off the fuel tank manually before storage, or to empty the long aux fuel hose when finished with it.

I've tried looking at the schematics, way over my head.

What wires do I need to supply power to, to force the fuel pump on, even when the float switch is satisfied? Are those wires behind the gage panel by chance? Hoping aimed smart electrical people can help, thanks.

 

[Scoobyshep]

You can either wire a bypass switch to float 2 or go straight to the aux pump E1 and apply power there. If it were me, id go straight to the fuel pump. Keep in mind that forcing this on can cause an overflow, So use with care. I dont think this mod can be done in the control cube, Im fairly sure that the float module (A9) is in the box (admittedly my 803 hands on time has been minimal, 003 i can tell you in my sleep) .

 

[kloppk]

I'd suggest connecting your toggle switch across the FL2 float switch and not do it by providing power directly to the Aux Pump. Providing power directly to the pump will backfeed into the A9 possibly damaging it.
Wiring to the FL2 circuit would require removing the end panel covering the fuel tank.

 

[dutchofsc]

Great point, I don't want to back feed and damage anything

I'll get the panel removed and see what the best course of action is, I'd prefer to not have to cut up the original wiring. Any recommendations?

Soon I'd like to get the remote start from you, maybe Santa will bring me one

 

[Toolslinger]

May I suggest using a momentary switch... I'd hate to get distracted and leave it on...

 

[dutchofsc]

Great point, I've spilled enough diesel in my life, don't need to spill any more. I might put the momentary switch near the fill, so I can actually see the fuel rising in the neck.

 

[kloppk]

The connection between the A9 and the float switch is done with a 4 pin Molex connector.
To do the mod without cutting any wire could be done by building a little adapter like with a male and female Molex connector to tap into the FL2 circuit.

Something like this...

 

[Guyfang]

This is what I would do. You can always change it back if you find you dont like it, without jumping through hoops. The connectors and pins are easy to find.

 

[dutchofsc]

Great idea and great advice, thank you both.

Can someone share links to where to buy the plugs and pins? I'd like to get this done this week.

 

[kloppk]

Housing and pins one end
Molex Housing P/N 3092042 DigiKey Housing

Molex pins P/N 2092103 DigiKey Male Pins



Housing and Pins other end
Molex Housing P/N 3091042 DigiKey Molex Housing

Molex Pins P/N 2091104 DigiKey Molex Pins


Pins can be soldered onto the ends of your wires and snapped into the housings.
I've used Molex connectors a lot.

Let me know when you want Santa to load your Remote Start system on his sleigh

 

[2Pbfeet]

+1 on the Molex adapter cable.

FWIW: I'm not perfect, so like to have an Molex extractor/ejector tool handy.
e.g. https://www.amazon.com/JRready-ST5265-Extractor-Connectors-Insertion/dp/B0C4P1FBHY

All the best, 2PbFeet

 

[dutchofsc]

Order placed, I get enough to make 2 and have spare pins, and still under 10 bucks with shipping.

I'll keep you posted

Can't wait for that Christmas present !

 

[DieselAddict]

If it saves you any time, order a molex extension cable and mod it. Super easy to find on amazon.