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So i work a lot with automotive type relays....
I made this circuit for general "selector" functions where the press of any one of an unlimited number of buttons will turn of everything else and turn on whatever is related to that particular button.

https://www.circuitlab.com/circuit/ea2337/pushbuttonselector/

Its seem to be working very responsive and reliably.

But if you manage to hold down two buttons and let go at the exact same time, it may let you power up more than one circuit at a time (and i guess more if your an octopus). I'd like to prevent that somehow. I've tried to reduce the capacitor size, but that is not really a complete solution since it just narrows the time window for button release. And it also affects the reliability of the circuit.

I was thinking about adding a resistor right after the switches to make the switching circuit pull a litlebit more power while the buttons are pressed. Then use some sort of current sensing circuit to trip a NC relay that would reset the entire circuit.

If one pressed button equals X mA then how to make something happen when current drawn by the buttons is 2X or more.

Hope that was explained clearly enough, maybe i am going at this all the wrong way.

Any and all comments and suggestions are greatly appreciated.

What are the un-named nets at the anodes of D4 and D9 connected to?

Your switches will wear prematurely because they are passing large current spikes on closing as they charge up the 100uF caps.

The leads running away from the relays may go to power an indicator light, a bigger relay for large loads or directly power the desired load if the current draw is low and same voltage as the relay circuit.

The switches i most commonly would use are rated at 5-15A at 220V so in 12v-24v use just for this.... i cant imagine a 100uf cap being causing much harm, am i wrong?

What you want will not be possible, try to see it as a feature (to engage two loads).

Change diodes to 1N4007 (Radio parts are a no go in automotive). Very likely the relays will have only 80 Ohms … The switches will stand that.

I made the suggestion:

• To show the principle of a detector for “two buttons pressed” (whatever “something happen” would be, THIS is your problem). This small transistor is bad in automotive (radio part).

• To show what CL offers on Time Domain simulation to simulate simple circuits (I apologize for badly misusing the “time controlled switch”, there are several possibilities to achieve the “buttons”, but this one is catchy).

Go to Simulate / start Time Domain Simulation (or simply press F5).

This circuit may not reliably work in automotive environment (without some protection) ...

Regards, Sancho