Racetronix universal fuel pump harness question..
#1
Racetronix universal fuel pump harness question..
This relay looks very simple I just have one question. There is a wire right best the positive wire that you hook to the alternator that says "Battery Negative".. I guess I'm just confused why this is right next to the power wire that comes off the alternator?
Does this have to go to the negative side of the battery or can I just ground it to the body or engine? If it does need to be used I will have to cut it and extend it to reach a ground from the alternator...
Does this have to go to the negative side of the battery or can I just ground it to the body or engine? If it does need to be used I will have to cut it and extend it to reach a ground from the alternator...
#3
TECH Addict
I've seen some motor devices like that(Water pumps, fuel pumps) that want the connection to be at the alternator end ,, it helps keep noise down in the electrical system, then you can ground to the alternator ground lug as well..
#5
TECH Enthusiast
I believe that ground is for the relay. It wouldn't need to go the to battery, but it does need to be grounded. It is used to close the relay when the small lighter gauge red wire on the other end of the harness goes hot. The lighter gauge wires in a harness like that are always the ones used to trip the relay, and the heavy gauge wires are the ones that carry the main current to the device your intending to control with the relay. The signal current flows through that light gauge red wire to the relay, then out through that "battery negative" you are concerned about. This current is what would activate the relay. Without it grounded it will not complete the circuit, and the relay will not close, and thus the fuel pump wire will not be hot. The outer housing of the alternator would work, or anywhere on the head around there would also work, to avoid having to extend it.
#6
I believe that ground is for the relay. It wouldn't need to go the to battery, but it does need to be grounded. It is used to close the relay when the small lighter gauge red wire on the other end of the harness goes hot. The lighter gauge wires in a harness like that are always the ones used to trip the relay, and the heavy gauge wires are the ones that carry the main current to the device your intending to control with the relay. The signal current flows through that light gauge red wire to the relay, then out through that "battery negative" you are concerned about. This current is what would activate the relay. Without it grounded it will not complete the circuit, and the relay will not close, and thus the fuel pump wire will not be hot. The outer housing of the alternator would work, or anywhere on the head around there would also work, to avoid having to extend it.
And just double checking the "redundant pump and relay chassis ground" goes off the body straight to the fuel pump right?
#7
TECH Enthusiast
Thanks for the info. I'll just have to cut the heat shrink and pull the ground out of the loom a little. Then run my wire off my hobbs switch to the activation wire..
And just double checking the "redundant pump and relay chassis ground" goes off the body straight to the fuel pump right?
And just double checking the "redundant pump and relay chassis ground" goes off the body straight to the fuel pump right?
Maybe someone from Racetronix will chime in and confirm, but I'm confident the diagram is mislabeled. If not mislabeled, confusingly labeled at least.
Last edited by ScottyBG; 02-25-2017 at 11:26 PM.