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Fri Jun 20, 2014 3:04 pm

If one happened to score another rear defrost switch who happened to place it in one of the empty locations on the instrument panel for a Kill Switch, where would one cut the wire on the fuel pump?

Since the switch is designed for little load via a relay, i don't want to melt anything ;).

The fuel pump must have a relay somewhere in the line so cutting the line in the appropriate place is critical. Can i cut one of the two wires located at the fuel pump itself and be safe?

Thanks!

Fri Jun 20, 2014 8:15 pm

In other words. Where can I safely cut the fuel pump wire in order to install a kill switch through a fake defrost switch on dash that is relay dependent.

Thanks.

Fri Jun 20, 2014 9:53 pm

Do you intend to add a relay to do this? You refer to 'relay dependent'....

You can also interrupt the wire to the starter solenoid thru that switch....

You (IMO) are on the right track for a kill switch in plain view that is easy to use all the time, unlike those that are not accessible from the drivers seat. :D

Fri Jun 20, 2014 10:56 pm

You would want the kill switch located to the left of the steering wheel so that one of your passengers could not easily turn it off when messing with the heater or radio. Have no idea on the amp rating of the defrost switch, but the fuel pump doesn't draw all that much.

Sat Jun 21, 2014 1:49 am

A good alternative is to switch the coil, either power or ground wire. No spark, no start.

Sat Jun 21, 2014 2:02 am

It is a simple matter of cutting the earth to the fuel pump and result is no go, a simple toggle is great but if you can get the same result from one of the dash switches then I see no need for relays and such.

Sat Jun 21, 2014 4:57 am

it's a great idea, i have thought about doing it, but..
if you forget to switch it off, then there's no protection.
i'm thinking of a non latching switch that you have to push when you turn the key, there's no forgetting to turn it off, hide it out of sight, but still easily accessible.
i was also thinking about a "start" button in plain sight, and connect it to an alarm, because if there's a button that says start on it, an intruder is likely going to push that one first ;)

Sat Jun 21, 2014 5:38 am

I've always wanted to hide a magnetic reed switch in the steering column, and add a strong magnet to my keychain.
That way whenever it's my keys in the ignition, it will fire right up, but anyone hot wiring it or otherwise trying to steel the car without my set of keys will have an additional layer of difficulty.

I think the key to any kill switch is convenience and forced habbit. Otherwise, in 6 months you'll stop using it.

Sat Jun 21, 2014 8:21 am

Syncroincity wrote: A good alternative is to switch the coil, either power or ground wire. No spark, no start.

I see the two wires going into the fuel pump. My question is can I splice into one of those wires and use a defrost switch safely?

If I tap into the coil where would I find that wire?

Sat Jun 21, 2014 9:02 am

Phishman068 wrote: I've always wanted to hide a magnetic reed switch in the steering column, and add a strong magnet to my keychain.
That way whenever it's my keys in the ignition, it will fire right up, but anyone hot wiring it or otherwise trying to steel the car without my set of keys will have an additional layer of difficulty.
Here u go... http://www.thesamba.com/vw/forum/viewtopic.php?p=4571909&highlight=magnet#4571909

Sat Jun 21, 2014 9:26 am

Instead of a toggle switch, I would prefer a momentary switch that allowed current during the 'start' position but did not affect the 'run' position. That way, you would press and hold the switch during starting, it would always reset to the 'no-start' position without you having to remember to switch it back, and there would be no risk of a passenger (or yourself) accidentally switching off the engine while driving.

Sat Jun 21, 2014 12:38 pm

sanchius wrote: Phishman068 wrote: I've always wanted to hide a magnetic reed switch in the steering column, and add a strong magnet to my keychain.
That way whenever it's my keys in the ignition, it will fire right up, but anyone hot wiring it or otherwise trying to steel the car without my set of keys will have an additional layer of difficulty.
Here u go... http://www.thesamba.com/vw/forum/viewtopic.php?p=4571909&highlight=magnet#4571909

Many thanks for the link.

Here's the same question I am asking and I am not super clear on the answer...
Perhaps someone knows if splicing into the fuel pump wire a few inches up from the pump is safe to tie a defroster switch into?

"""While I do appreciate the input, I find that no one's answered the question I answered when I reactivated the thread. I was under Winston today when I installed the resistor fix, which seems to have gone as well as I might have hoped.

I only saw the one power wire coming out of the fuel pump, and that ran straight back to the rear engine compartment. Does anyone have an idea of how much current (after the resistor mod) is running through it? Would a loop with, say, 16 gauge wire up to a switch in a cab melt a defroster switch (found that, today) in the console? """

Sat Jun 21, 2014 1:49 pm

Pull the defroster switch out and see if it has an amp rating stamped or molded on it anywhere. You can probably find out what kind of amp draw the pump has from either examining the pump closely or looking for something similar on eBay and see what specs they give.

Sat Jun 21, 2014 2:18 pm

NO, it is not safe to splice a dash switch into the fuel pump power wire. You could burn down the van or cook your fuel injection harness. The problem isn't the switch, it is that there is no fuse for the fuel pump power. A short to ground on your added wire run could be serious. Better to run the pump ground wire to the dash and put the switch on that, with the other side of the switch tied to ground. Also then you only need to run a single wire, not up and back like a power wire splice would need.

Mark

Rjhdog wrote: ....Here's the same question I am asking and I am not super clear on the answer...
Perhaps someone knows if splicing into the fuel pump wire a few inches up from the pump is safe to tie a defroster switch into? .....

Sat Jun 21, 2014 2:42 pm

You want to disable the ground wire to the switch--not the power wire as has been mentioned several times.

No ground = no pump, and there is going to be a no load on the grounding wire on the pump to that switch.

This is exactly what you want to do,--nothing else, if your going to disable the fuel pump, on that defroster switch.

Sat Jun 21, 2014 2:59 pm

Yes there is a load on the ground wire, exactly the same load as on the power wire. Same amps come out of the pump on the ground wire as go into the pump on the power wire.

Mark

Sat Jun 21, 2014 4:41 pm

So,
Your saying that on a DC circuit the ground is carrying the same amperage as an AC circuit?

I'm not sure about this one.
I'm waiting for my Buddy Marconi to call me back on this to 100% set me straight on this.

Sat Jun 21, 2014 4:58 pm

I was just talking to Guglielmo on my Ouija board and he confirms that power and ground wires see the same current.

The big advantage of switching the ground wire (as noted above) is that you only have to run one wire to the switch.

In addition -- should it happen that that wire shorts somewhere all that occurs is that the switch does not cut out the pump.

I cannot say for sure but IMO the pump draw is low and those rocker switches should have no problem with it.

Sat Jun 21, 2014 4:58 pm

I didn't say anything about an AC circuit. We are talking about a car with DC circuits.

Mark

Terry Kay wrote: So,
Your saying that on a DC circuit the ground is carrying the same amperage as an AC circuit?

I'm not sure about this one.
I'm waiting for my Buddy Marconi to call me back on this to 100% set me straight on this.

Sat Jun 21, 2014 5:01 pm

Terry Kay wrote: You want to disable the ground wire to the switch--not the power wire as has been mentioned several times.

No ground = no pump, and there is going to be a no load on the grounding wire on the pump to that switch.

This is exactly what you want to do,--nothing else, if your going to disable the fuel pump, on that defroster switch.

Thanks mark and terry.

So if I understand this correctly, splice into ground wire and run one wire up to dash switch. On the other side of switch run to a ground.
Any concern with a relay?