Kill switch, 1997 k1500 pickup

[aj_08]

Hello,

I was thinking of adding a kill switch by interrupting the power between the computer and the fuel pump relay, which I believe is a dark green and white stripe wire. This dark green and white stripe wire is one of five wires going to the fuel pump relay, correct if I am wrong please:
1. Red : fuel pump prime
2. Grey: to the sender, powers pump
3. Orange: fuel pump/oil pressure switch
4. Dark green/white: fuel pump relay control from vehicle control module
5. Black and white stripe: ground

To splice into the dark green and white stripe wire,, the underhood fuse box needs to be opened to access the wires underneath, unless there is another way to do this without disrupting the box?

Alternatively, there is a grey wire from the fuel pump relay that goes to the fuel pump and runs along the frame on the drivers side. One can potentially splice into this grey wire. Unsure if it's "better" to disrupt the computer to the relay signal (dark green and white stripe wire) or the relay signal to the fuel pump (grey wire)?

Does anyone recommend using another kill switch idea that does not involve the underhood fuse panel and instead, uses the interior fuse panel to the left of the steering wheel or other wires under or within the dash?

Any ideas or feedback is welcome. Thanks.

 

[Schurkey]

Disabling the fuel pump relay control means the engine will crank a long time before it builds oil pressure. When it does, the oil pressure switch will bypass the relay and the fuel pump runs like normal. Engine starts, thief drives away.

If you're going to disable the fuel pump, you need to do it in the main wire that powers the pump, not at the relay.

Download the service manual set for your vehicle, look at the fuel pump wiring diagram. May be the easiest way to accomplish this is to splice your switch into the fuel pump fuse socket using jumper wires and a separate fuse holder.

 

[aj_08]

Disabling the fuel pump relay control means the engine will crank a long time before it builds oil pressure. When it does, the oil pressure switch will bypass the relay and the fuel pump runs like normal. Engine starts, thief drives away.

If you're going to disable the fuel pump, you need to do it in the main wire that powers the pump, not at the relay.

Download the service manual set for your vehicle, look at the fuel pump wiring diagram. May be the easiest way to accomplish this is to splice your switch into the fuel pump fuse socket using jumper wires and a separate fuse holder.

Yes, good point about the oil pressure building up while cranking, and once it reaches a certain pressure, it bypasses the relay.

Therefore, the grey wire that comes from the fuel pump relay and travels to and powers the fuel pump may be the wire to splice. Even if someone cranks and cranks, there is no way power will travel to the pump since there is no bypass that powers the pump in this case, the power won't travel if the switch is closed.

The ECM-B fuse is the one for the fuel pump though....so this is what you are referring to.

 

[Carlaisle]

The coil is another option.

 

[aj_08]

The coil is another option.

Yes, another good suggestion. Could this potential flood the engine with fuel/ other drawbacks? Benefits of this method?

Ok, will look for the power wire with ign on that goes to the ignition coil. There are three wires I believe, I think it might be pink?. White goes to the tach input, white and black is the ignition coil out, and pink comes from the ecm-1 fuse. Does this make sense?

 

[Carlaisle]

If the fuel pump is working and the plugs are not firing and the would be thief is a moron there is a definite possibility of flooding/cylinder washdown.

You could also put a switch on the starter relay.

 

[k1500 97]

Yes, another good suggestion. Could this potential flood the engine with fuel/ other drawbacks? Benefits of this method?

Ok, will look for the power wire with ign on that goes to the ignition coil. There are three wires I believe, I think it might be pink?. White goes to the tach input, white and black is the ignition coil out, and pink comes from the ecm-1 fuse. Does this make sense?

This Sounds like the best option posted yet, cuz shutting off fuel for a kill switch isn't gonna do **** when the fuel line holds like a gallon of fuel. But taking the spark away will kill it isntanly.

 

[BigReb95]

Yes I have a kill switch on my truck leading to the ignition coil wire, I have it on a relay to save the switch from burning out. Been there for 5 years and no issues.

 

[aj_08]

This Sounds like the best option posted yet, cuz shutting off fuel for a kill switch isn't gonna do **** when the fuel line holds like a gallon of fuel. But taking the spark away will kill it isntanly.

Yes, I see what you are saying. Good thing about the fuel shutting off mid drive is the truck will stop. Thieves may just ditch it there. With the spark, if the switch does fail the truck isn't going anywhere, in addition, there is always current running in that switch and is a higher risk for problems. A starter switch draws power once for every start and does not need to be on after it starts which is less risky I believe.

 

[scott2093]

Anyone have experience/opinions on the wireless/remote control relays? To avoid having a switch?