Fuel Pump Switch

[hayai_240]

Im planning on installing a fuel pump switch in my car as an added security for my 240. I was wondering if it is possible to wire the fuel pump switch to my A/C button? The A/C on my car isn't working anymore so i think it would be pretty creative to use the existing A/C button as a fuel pump switch. Has anyone done this before? Is it even possible? If it is, could someone tell me which wires to use?

Thanks

[Looneybomber]

I don't own a 240 and never have. If your car is a manual, it should have a kill switch on the clutch, as in if it's not depressed, you can't start your car. You could just use one of the wires going to that switch and extend it so that you can then run it through the AC switch. It would be easier than splicing the wire to the fuel pump, plus I have no idea what kind of amperage that switch can handle. If it's a very low wattage switch, you could burn it up with the fuel pump, but it's not likely.

I can't actually give you any concrete data that you're looking for, just ideas

[qsiguy]

Definitely YES. You can do just about anything you want. With that particular switch you would connect that to a relay and that would control the fuel pump. The typical relays we use handle 30 amps. Killing the clutch safety switch would be easier but not very effective as a kill switch, it's to easy to circumvent the starter circuit. Fuel pump or fuel injection fuse would be very effective.

I've wired kill switches to many different switches, parking lights, power window buttons, cig. lighter, cruise control buttons, steering wheel audio controls, etc. Most of the time you can wire it so the OEM button still functions as well.

I don't have a diagram of that button for your car but it would be easy to figure out how to use it. Pull out the panel so you can get to the wires (assuming there are wires on it) and use an ohm meter to figure out which two terminals/wires are connected when the switch is ON. Wire one of those terminals/wires to ground and the other to the coil of a relay. The other side of the relay coil would connect to 12VDC+ switched power that has power when the key is in the ON and CRANK positions but OFF when the key is off. Then wire the normally open contacts of the relay to your fuel pump or FI fuse. The fuel pump will only have power when the A/C button is on and the key is in the ON and CRANK positions.

This may have confused you but it is quite simple. If you want I can write up a diagram to show you.

OK, did a diagram. Here it is.


Modified by qsiguy at 3:36 PM 8/3/2006

[SR20Monster]

sweet just what I was looking for.. now I just have to find which wire in the car goes to which wire on the relay!

[lofapoo]

Damn, you beat me to the idea.

I was thinking about installing a fuel pump kill switch on the A/C button, since mine doesn't work anyway.