BX fuel pump wiring

JackJ

Member

Equipment
BX1870-1
Mar 14, 2016
264
3
18
Indiana
As detailed in another thread, the engine-side drive shaft boot on my BX1870 self destructed, and in flailing about it severed the wires to the fuel pump. I'm going to splice/solder new wire in, but I'm a little confused.

While the wiring diagram shows one black and one yellow/red lead going to the pump, I've got one black and two yellow/red (see attachment below). Am I safe in assuming it doesn't matter which yellow/red connects with which across the break?

Probably needless to say, but I'm an idiot when it comes to anything electrical, and it doesn't bother me if anyone reminds me of that fact, so clue me in! I'm assuming this yellow/red is the positive lead and that it makes a stop at the fuel pump while continuing its way to other components that are always on when the key is turned. But I can't figure out if the order of the connections is meaningful, except that presumably not or the two wires wouldn't be the same color scheme.

Thanks!

Jack
 

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jkcolo22

Member

Equipment
BX25D
Jan 5, 2017
291
4
18
Castle Rock, Colorado
As detailed in another thread, the engine-side drive shaft boot on my BX1870 self destructed, and in flailing about it severed the wires to the fuel pump. I'm going to splice/solder new wire in, but I'm a little confused.



While the wiring diagram shows one black and one yellow/red lead going to the pump, I've got one black and two yellow/red (see attachment below). Am I safe in assuming it doesn't matter which yellow/red connects with which across the break?



Probably needless to say, but I'm an idiot when it comes to anything electrical, and it doesn't bother me if anyone reminds me of that fact, so clue me in! I'm assuming this yellow/red is the positive lead and that it makes a top at the fuel pump while continuing its way to other components that are always on when the key is turned. But I can't figure out if the order of the connections is meaningful, except that presumably not or the two wires wouldn't be the same color scheme.



Thanks!



Jack

Test them with a multimeter or a continuity tester. I’d be surprised if they configured it the way you are saying... usually the manufacture won’t splice a positive in the middle of the run like that. Especially with a fuel pump that is probably separately fused. Can you post a picture of the manual you are looking at?

Edit: I looked at the WSM. You need to test. You should find that with the key on, your test device indicates that at least one of those Red/Yellow wires shows voltage with key on (with your other lead on black/ground. Note: if using a continuity tester, you need to use the kind without a battery. Report back findings... one of those RY wires is your positive for fuel pump... the other might be a blinker wire... it which case it should cause your continuity tester to either flash or show 12v/0 (alternating) on a multimeter with you hazards on. And then you will need to look for the other end of the wire to connect to...


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Dave_eng

Well-known member
Lifetime Member

Equipment
M7040, Nuffield 465
Oct 6, 2012
5,107
926
113
Williamstown Ontario Canada
As detailed in another thread, the engine-side drive shaft boot on my BX1870 self destructed, and in flailing about it severed the wires to the fuel pump. I'm going to splice/solder new wire in, but I'm a little confused.

While the wiring diagram shows one black and one yellow/red lead going to the pump, I've got one black and two yellow/red (see attachment below). Am I safe in assuming it doesn't matter which yellow/red connects with which across the break?

Probably needless to say, but I'm an idiot when it comes to anything electrical, and it doesn't bother me if anyone reminds me of that fact, so clue me in! I'm assuming this yellow/red is the positive lead and that it makes a top at the fuel pump while continuing its way to other components that are always on when the key is turned. But I can't figure out if the order of the connections is meaningful, except that presumably not or the two wires wouldn't be the same color scheme.

Thanks!

Jack
I looked a the wiring diagram for a model very close to yours. The Red-yellow wire goes two places both fed by a 15 amp fuse.

The fuel pump and the alternator. The alternator wire would be to trigger the alternator on when you turn the key to on in the same way the fuel pump is turned on.

It wont matter which Red-yellow wires connects to its mate as they both join together in the harness.

The black wire is the fuel pump ground.

Dave
 

jkcolo22

Member

Equipment
BX25D
Jan 5, 2017
291
4
18
Castle Rock, Colorado
I agree with Dave, assuming you do have another RY wire to connect the wire that you don’t connect to the fuel pump (and that we can’t see in the picture). But according to the WSM for your tractor, an RY wire does also service blinkers and that one would be switched. So connect them wrong and you might not destroy anything, your hazards will just be constant “ON” (not blinking) with key and your pump will not have power so no starting. Which is why I still recommend testing...
 
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