I've been reading around, but I still do not understand the technicalities of the whole thing. What i am hoping to do is to place a kill switch on my fuel pump line, which will default to an open circuit. When i press the momentary contact switch, it'll close the circuit and keep it closed. When the car is off, it'll default to closed again. Anyways, the12volt showed this, what I think is called a latching setup:



In analyzing this image, when i press the momentary contact switch, it provides pins 85 of both relays with power, which will result in a closed circuit. Hopefully I have that much right.

Now the problem is that the diagram deals with the starter, whereas I want the fuel pump. So here's my question:

1) Motor side and Key side of starter? What are those? What would they be on the fuel pump?

2) Does this even apply to a fuel pump, though? Or do i need to change the wiring?

3) Would i diode be necessary?

4) When wiring, do i solder the wires to quick disconnects, which in turn connect to the pins? Or do you guys use relay sockets?

Thanks! Hopefully somebody can clear this up so that everyone has a better understanding of the relay kill switch.

 

you can not use this on fuel pump. you see the fuel pump needs to be on constant once car is on.

that momentary switch is what makes both relays work, once the switch is open again, 85 and 86 will have no power, thus 87 and 30 have no power....thus the second relay's 85 has no power and thus 87 and 30 has no power either.

this diagram as you can see if for a "passive starter kill" not a fuel pump!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by l337hxr &raquo;</TD></TR><TR><TD CLASS="quote">you can not use this on fuel pump. you see the fuel pump needs to be on constant once car is on.

that momentary switch is what makes both relays work, once the switch is open again, 85 and 86 will have no power, thus 87 and 30 have no power....thus the second relay's 85 has no power and thus 87 and 30 has no power either.

this diagram as you can see if for a "passive starter kill" not a fuel pump!</TD></TR></TABLE>Ditto that , it will NOT work for fuel pump 94
PS go to AWESOME KILL SWITCH scroll down and you will see a true passive latching setup you can use for fuel pump


Modified by fcm at 3:36 PM 3/28/2005

 

a kill switch would be easy to hook up, i would think just using a relay with a switch somewhere. as for why you are doing it, as an additional anti theft thingy?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hks85 &raquo;</TD></TR><TR><TD CLASS="quote">a kill switch would be easy to hook up, i would think just using a relay with a switch somewhere. as for why you are doing it, as an additional anti theft thingy?</TD></TR></TABLE>

Yeah, I thought i'd hope to achieve that. I just never knew it'd be impossible with the fuel pump.

 

I just used a simple rocker switch, one wire to one prong, one to another, really simple, no relays. Works great.

 

It should work. The second relay is constantly on once the switch is closed. Pins 87 and 85 on the second relay are connected. Once the switch is pushed the second relay feeds itself 12 volts, keeping itself on until the ign switch is turned off. To use it with a fuel pump just find the hot wire to the fuel pump, cut it. And then hook one end to 87 of the first relay and hook the other end to pin 30 of the first relay.
Try it with a light if your not sure. Hook pin 87 to 12 volts, hook pin 30 to one side of the light, ground the other side of the light. Hook everything else up as it is shown in your diagram.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by matt_in_sd &raquo;</TD></TR><TR><TD CLASS="quote">It should work. The second relay is constantly on once the switch is closed. Pins 87 and 85 on the second relay are connected. Once the switch is pushed the second relay feeds itself 12 volts, keeping itself on until the ign switch is turned off. To use it with a fuel pump just find the hot wire to the fuel pump, cut it. And then hook one end to 87 of the first relay and hook the other end to pin 30 of the first relay.
Try it with a light if your not sure. Hook pin 87 to 12 volts, hook pin 30 to one side of the light, ground the other side of the light. Hook everything else up as it is shown in your diagram.</TD></TR></TABLE>

Oh now i'm confused! Some people say it works and some others don't!

 

Prove it to yourself by using the circuit with a light bulb. If you build what is drawn, once you push the switch both relays will remain energized as long as ignition is on.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by erikiksaz1 &raquo;</TD></TR><TR><TD CLASS="quote">

Oh now i'm confused! Some people say it works and some others don't!</TD></TR></TABLE>It will work 94

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fcm &raquo;</TD></TR><TR><TD CLASS="quote">It will work 94</TD></TR></TABLE>

Woops, i was reading it wrong. It'll work for what it was intended, which was the starter. But as a fuel pump kill switch, it will not. Right?

 

i usw this exact same setup on my 99 civic to start it you have to hold down the cruise control button to start the car.

 

okay i'm am an electrical engineering student 3rd year and i am TELLING you that the CURRENT diagram you are showing is FOR a STARTER ONLY....because its a Depressable switch, once you let go, the switch opens again......

A FUEL PUMP REQUIRES you to have a constant source. So you MUST change the wiring on those relays a bit. And you probably can't use a PUSH-Button switch...and you shouldn't be using a push-button on a fuel pump anyway...like someone else mentioned get a rocker switch...

and no it is not impossible to do for fuel pump, its rather quite easy...just get a rocker switch and a relay.

 

https://honda-tech.com/zerothread?id=1194912


Modified by l337hxr at 10:24 AM 3/29/2005

 

Not this one <TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by erikiksaz1 &raquo;</TD></TR><TR><TD CLASS="quote"></TD></TR></TABLE>
This one https://honda-tech.com/zerothread?id=1186138 6 posts down, sorry I don't know how to bring up the post itself 94

 

It will work for both. once the second relay is energized it will feed itself 12 volts, pin 87 is tied to 85, until the 12v from the ign is removed. The reason it works for the starter is that you have asecond switch (IE ignition switch) that is in series.