banging my head, 1 wire, 2 functions

Is there supposed to be a quiescent condition where neither relay is on? If the input is left floating what is going to happen with the relays?

I'd suggest adding zener diodes on the original transistor drive circuit to provide isolation in the inactive condition where neither relay is supposed to be energized. Put them in series with the base of the transistors, and put the base resistor in the input from the steering wheel wire. When the input is open, the two zener diodes in series will not conduct (select a value of 6V or so), since they'll below 12V. When you have an active input of 12V or ground, the corresponding zener will begin to conduct since it'll have 12V across the single zener, and provide the current to the transistor driver stage.

at the risk of sounding stupid i'm gonna ask a question, feel free to criticize me, would wiring the trigger with the same polarity make this problem go away, since he's using relays i mean, does he really need a negative and a positive signal, if he were to just use a straight negative signal to activate both relays one would be going negative to negative and the other inverting from negative to positive, or the other way positive signal triggering both relays, or would there still be feedback ?, or is this too simple and i don't know what i'm saying, again feel free to criticize.commit your way to jehovah and he will act in your behalf. psalms 37:5

There's two different functions he's trying to control with a single wire, and probably aren't supposed to happen at the same time. To individually control the two functions means there has to be a different signal to trigger each one. In this case, one is a +12V positive signal, and the other is a negative going ground switch signal. When neither one is active, it's presumed to be just left as an open circuit.

oh, i now re read, sorrycommit your way to jehovah and he will act in your behalf. psalms 37:5

do you have a part number for a zener diode? Jon

Installer/Help Technician

---coral springs florida---

mecp certification is not always needed. I have it and it has not helped me out at all. my experience out shines it.

No requirement for wattage, it'll be limited by the base resistor that'll be inline, and non conducting in the standby condition. They're typically 1/2W, which would be fine. Like I said, a breakdown voltage of about 6V would do. The 6.2V one shown on the fairchild listing should be suitable. Check mouser.com for quantities under 1000 pcs.

Since it looks like it wasn't clear what I was thinking of, here's a diagram based on Kevin's original circuit- Relay R1 will switch on with a 12V input, and R2 will energize with a ground input. When the input is left open, neither relay will be on.

The Zener diodes are 1N5234B   The other diodes pictured are 1N4001s