latched on/off momentary w/ brake kill

I am wiring a manual torque converter lock up switch for my tow vehicle. This is normally a simple task. One wire in the transmission solenoid is tapped and grounded manually with a toggle to lock the t/c. A 3.3 ohm resistor gets wired in line as to not trip a check engine light. Piece of cake. Why do it the easy way I say? What I want is to create a latched relay so I can lock and unlock the t/c with a momentary button. While the t/c is locked I want a led to light up. If the t/c is locked and I hit the brake I want it all to turn off. I know it is possible but my brain isn't functioning as it should currently so I have turned to the pros here. I have used your diagrams many times,and love the site. Long time guest first time poster! About time I say. Can someone post up a diagram to clear my cobwebs! Thanks in advance.

Why not just a latching switch to control a normal relay? Otherwise the following provides a toggle/latching signal, but you'd probably have to add a transistor etc to handle the relay's coil current....

Help me understand this better.

The way I took it you actually have two switches.

One to set the lock ( a Pushbutton ) and the Break switch to Unlock.

An Led lights when you push the button and it goes off when you push the break switch with your foot

Am I missing something?

John DeRosa (Hotwaterwizard)

Stockton California

When in doubt, try it out !

You have it correct except i would like to be able to turn it on and off with the momentary button (lighting the led when its on) The brake shuts it off in case I forget to do it manually

Basically one way to turn it on (button) and 2 ways to turn it off. (button or brake)

So what are you thinking? I am hoping to get this wrapped up and installed this weekend.

Two Push buttons  and the break switch would be easier

John DeRosa (Hotwaterwizard)

Stockton California

When in doubt, try it out !

Thanks for the reply hotwater. I will fall back to 2 buttons if i cant make 1 work. Keep in mind the input that the system needs to lock the t/c is a ground not 12v.

Does anyone have a diagram for- Latched On/Off Output Using a Single Momentary Negative Pulse - Negative Output

The following are almost equivalent latching relay circuits but for +12V output. To [i[]invert for a grounded output, a second SPST relay would be added to the output - ie, ouptut to #86; ground to #85 & #30m with #86 being the grounded output when the first relay is latched. The circuit diagram shows a pump as the output whereas the wiring diagram shows the +12V output with the pump omitted, and includes an optional Normally Closed momentary switch to break the circuit if wanting to do so without removing the main +12V power. FYI - the two +12V sources in the first circuit diagram can be the same (as indicated by the dashed interconnection in the second wiring diagram). It was drawn as two separate +12V sources to highlight that they could be independent.    And there is still the previous "Toggle Switch" using inverters which could control a relay of either polarity. It should be easy to add a pulse- or switch-off (from a brake switch) since a hex inverter IC will have 4 unused inverters and quad NOR or NAND ICs will have 2 spare gates, but I haven't worried about that for lack of response. And yes - the +V and GND power connections to <whatever> gates (inverting, NAND, NOR) are not shown, but they are usually pins #14 and #7 on hex inverters and quad-gate Integrated Circuits. (We should be using an 8-pin PIC - so much easier circuit-wise!)