Custom Electric Parking Brake Switches

I've been asked to figure this out, and I know from wonderful past experience with this forum that there are gentlemen on here that can do this with their eyes closed. So - I come to you hat in hand for a solution, please & thank you: This is a custom electric parking brake installation on a snarly 4x4 retro-build. During off-road adventures, the necessity occasionally exists for just one wheel to be locked. Therefore... The owner wants three switches; LEFT brake on/off RIGHT brake on/off BOTH brakes on/off In each case, the switch needs to be illuminated, and push-click-on/push-click-off. The squirrelly part is this: The mechanism does not operate like a light; it is not on-when-energized and off-when-de-energized. Rather, it operates by reversing the flow of power. I'm still getting my head around it, but as I understand it there is ALWAYS power going to the mechanism. The variable is...to which side (pole/contact) the power is being sent. I'm guessing there is no return spring or other mechanical retract function. Instead, the brake is cycled to the OFF position by reversing the flow direction of the current. For this reason, the switches need to be wired so that they are in the "off" ("out"..."up"..."not depressed") position when the brake is OFF. This will be the usual mode for normal driving and most off-road driving. I'm assuming that it is not possible or simple to accomplish this with fewer than three switches...but if it is - please enlighten me! TIA!

Do you have a schematic for this mechanism or a manual? It might help to visualize better.

That's a good thought. I'll look.

Egad. This is what separates the men from the boys. These things make my brain hurt, but to some of you - they positively sing. Note that the actuators will be installed...but the BCM and all that circuitry to the left will not be there. Instead, separate/dedicated circuits will be fabricated & run to the LH & RH actuators. The puzzle is - am I right to conclude that there is ALWAYS power going to the actuators? And we just need to figure out which side needs to be energized in order to activate the brake...and therefore which side needs to be energized to DE-activate the brake. I think.

The way it has been explained to me seems improbable. I would have expected that the mechanism has a spring of some kind that applies the parking brake when the power is off. (The DEFAULT) Then when the power becomes available once more--and the signal is sent to release the brakes--the spring releases. But I'm being told that - no - the brake is applied by energizing one side of the actuators...and released by reversing the flow/direction (and sending power to the other side of the actuators) <scratches pointy head>

Would it be possible to wire them like reverse polarity door locks, then? Something like this for example: https://www.the12volt.com/relays/relaydiagram4.html Or does power need to flow constantly to keep pressure applied?

https://timers.shop/Exhaust-CutOut-Controller_c_22.html?gad_source=1&gclid=Cj0KCQjwj4K5BhDYARIsAD1Ly2rXk1ky5XFoxekSKzP05ArN9r5HwVi0pXv-S23z0cQyYj6oQL9MhGAaAkxLEALw_wcB Two of these, one for each side. Set up for input mode 3 (latching switch). Diodes on output of 'both' switch to each controller. You'll need to adjust the operation time. Of course, need to ask. Is the customer needing system to work at all times? ie ignition off?

Or timersshop reversing motor controller with custom firmware. Maybe contact them, they're usually quick to respond.

Thank you for the input, gentlemen! This is still a W.I.P., and I am still awaiting some clarification on a couple of issues. Please don't abandon me - I promise to follow up when I have some relevant/helpful data!

241109: Okay! I initially drew up a sketch: And then my good friend & fellow member gave me a wee tip, and I've run with it! Here's a sample of what I found: So...I hope (and expect) to find a second matching switch (SPDT?) that will provide for the activation/de-activation of both brakes. But at least I am making progress! Thanks, the12volt!