I have 3 wires.

Wire A is connected to Wire B

There is also a Wire C


I want a type of switch, where, if there is power on Wire C, There is countinuity between wire A and wire B. But if there is no power on Wire C, wire A and wire B is disconnected.

Wire C will be a 12V feed, and wire A and B would be a variable 0-5V.


How do I wire this?

 

You need a relay.

http://www.autoshop101.com/forms/hweb2.pdf

 

Thanks for the reply.

I thought relays could only do same current...

I am wiring it up so my TPS only works when the starter is cranking, but disconnects the tps once the starter is dis-engaged.

 

Why?

 

my TPS is wacked, and i have a hyphy J-Spec throttle body on a USDM ECU.
It makes adjustment very hard, if not impossible.
I tried driving it without the TPS connected, and it drives alot better.
But the car does not like to start with the TPS disconnected.

It would be something temporary till I can hunt down a USDM Throttle Body and USDM Bac Valve... The pulsing and hesitation is pretty damn anonying...

 

I have no idea what "hyphy" means, but the only difference between J-spec and US-spec TB's is the double-throttle actuator and linkage. The TPS and it's adjustment is exactly the same. It sounds like what you need is a new TPS, not a new TB.

What you want to do is not hard though. It would be best done at the ECU, since you have the TPS and start signals in the same place. You need a 5-pin SPDT relay. You'd cut the TPS wire and connect the cut ends to pins 30 and 87a (not 87), tap a wire into the ECU's start signal wire and connect that to pin 85, and ground pin 86. Pin 87 is unused. Basically the TPS signal will be interrupted unless the key is in the start position, in which case the relay will relay will complete the TPS circuit until you release the key. Compare the pin info to the doc I linked to and it should make sense.

I'd just get another TPS myself...

 

I believe I do need a new TPS too... but I decided to just do what most FC owners do.
That is pretty much how I wired it. I did it a slightly different way though...
I used a 4 pin relay, with pin 30 and 87 on tps, 86 on ECU wire 1C (starter), and 85 on ground.

And now... my next mod... electrical tape over check engine light.

Thanks!

also, hyphy is a word that black people use to describe going crazy. it is a word created by and for the lower class. i like using it because i want to act like every suburban peeps who think they can talk ghetto.

 

Dont try and take credit for my invention of the electrical-tape-over the check-engine-light mod you hyphy ******!

 

dats how we rol' it in da bay, son!