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How to wire switched relay for fuel pumps

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Old 11-06-04, 05:04 PM
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Hey, where did my $$$ go?

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How to wire switched relay for fuel pumps

I know this might not really go in this section but I figured it would be seen by other people with the same type situation here.


Here is what I've got, I'm wiring 2 fuel pumps right off the battery. I'm running 8 gauge with a 40amp fuse from the battery, it makes a Y into two 14 gauge wires. The 14 gauge wires will go to the fuel pumps (one to each obviously). Im putting a switched relay and a 20amp fuse on each of the 14gauge wires.

My question is, how do I wire the switched relays? There are 5 terminals on them. and here are the markings they have.....
85
86
87a
87
30

I know that I have a power in from the battery and a power out to the pumps. There is a ground in coming from the chassis and a ground going to the pumps.
Then there is a switch ignition wire to activate the relay and allow power thru to the pumps. I'm going to use the stock fuel pump power wire as the ignition trigger wire.

My main problem is I just dont know where any of those wires go. Can anyone help me out with that???

Thanks,
STEPHEN

Last edited by SPOautos; 11-06-04 at 05:07 PM.
Old 11-07-04, 01:56 AM
  #2  
Hey, where did my $$$ go?

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OK...here is what I think I've figured out. Someone please tell me if I'm correct....

87 - main power from from battery
30 - power going to pump
86 - ignition trigger switch (stock pump power line)
85 - ground to chassis.
87a - not used

Is that all I need to do? Can anyone confirm that this is correct??? Is the 87a really supposed to be unused and if so, at any point is there any power going to it that would make it smart to cap it off?

Thanks,
Stephen
Old 11-08-04, 02:46 PM
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Hey, where did my $$$ go?

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Anyone?
Old 11-08-04, 06:18 PM
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The 30 goes to the 87a when the relay isn't switched , so if not in use you should either cut the pin off , or remove the wire if your using a relay harness , and yes the 85 86 are used to energise the relays coil to cause it to switch , they can be connected either way ie , either one can be hooked up to the 12v source whilst the other goes to groung . You could simpilfy things buy getting a 87 87 relay , which would send power to both pins when the relay is switched , allowing you to power both pumps with a single relay.When I installed my pumps , I just used one relay and connected them in series , ie battery to + 0n pump #1 , then to + on pump # 2 , same with the ground , I have had no problems with this setup.
Old 11-09-04, 02:27 PM
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Hey, where did my $$$ go?

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Thanks man!!! Yea, I thought about just using one but decided to use seperate ones. They were only $10 each and I felt like them being 30A/40A was a little too close to what the amps could potentially pull and I just went on the side of caution.....for $10 why not haha

Anyway, thanks for the info

Stephen
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