DIY ADD Actuator ECU

Here's basically all the info my FSM has for the electronic ADD. It just shows which pins should have continuity with each other and which shouldn't. Doubt it helps, but figured I'd already looked it up anyways:

 

Thanks for the visual. Any idea what kind of current that motor pulls? (<5A fingers crossed)

 

I wouldn't think it would be more than 5 amps but I haven't measured it.

I do know the Transfer case and Diff lock actuators can draw around 10 amps if they are stalled but the ADD has a smaller motor.

 

Went ahead and having this manufactured after experiencing the mess of protoboarding it. Here is the only silver latching DPDT push button switch I could find. Super satisfying to press haha.

 

You can use the same aftermarket rear elocker switch on the front ADD motor. I'll dig up the info. I've done it before. You don't want the power to latch on. That will leave constant power to motor. It needs to be momentary and flip flop politarity to move which ever direction you need.

https://www.offroadwarehouse.com/product/low-range-off-road-front-toyota-elocker-switch-diyelsf


This is the rear actuator diagram, but same principle of operation. Wire colors are different.


If you end up with the 8 terminal switch this is the diagram for rear. You'll have to compare front wire colors to rear to determine the difference. Terminals 8 and 7 are for an internal led that lights when it locks.

 

Too late. But not a problem as that is why there's a feedback loop to the PMOS which stops current once the switch activates (hence why it's not just a DPDT switch). Much greater reliability than a mechanical toggle as well

 

So, turns out the Toyota FSM is not entirely forthcoming with the limit switch behavior and I had to basically invert the design because of it. The switches are not Normally Open. They are Normally Closed.

So during travel, the feedback would pick up voltage and turn it off, leaving the motor in a halfway state. To fix this, I had to swap polarity of the board, use NMOS instead of PMOS, and change the resistors to pull-down instead of pull-up. Thankfully this was doable on the 2nd iteration of the boards I had manufactured. It now works.Sadly this means the ground plane is now a +B plane, so I have to isolate it well, wherever I decide to mount it.


Final solution here:


The Molex plug is waterproof, and the whole set is only $5, so I'm definitely using them for future projects. I also poly-filled 4 pins with +12V and GND, so I can branch 2 extra circuits off the one input for other things, provided the total doesn't exceed the fuse ofc. Btw, the resistance of the motor is roughly 3-4 ohms, so pulls around 4amps.