40V 800W Brushless Motor Speed Controller - Need wiring help

Thread Starter


Joined Aug 12, 2023
I bought the BLDC controller pictured below to try to fix a Kobalt 40 Lawn Mower with a bad controller. I'm hoping someone here has experience with the same style controller that I bought. (There's a TON of videos on YouTube about eBike style controllers with a bunch more wires than mine has)

I can pretty well understand the 40V in, and power out to the motor connections.

What has me scratching my head is the 4 wire "Start Control Line" connector, and the poorly translated Chinese that says:
" The controller wiring is defined in the introduction picture. The control wire must be connected to the black wire and the yellow wire first, and then the brown wire, otherwise the protection will not start. If you are afraid to connect 2 switches, you can directly connect the black wire and the yellow wire. It is not necessary to short-circuit it."

The mower has a "START" button, which need to be pressed and held until the "RUN" bar is pulled back towards the handle bar. Then it is released.

The START switch has a set of leads that runs to the Kobalt Controller.

There are also a pair of wires that connects a NO micro switch activated by the RUN Bar, that flows in series through several other micro switches, to the Kobalt Controller.

I'm guessing the Black and Yellow wires on my replacement controller would go to the START switch.

I'm confused from there!

Connect Brown wire through the safety switches and the RUN bar switch to the Black wire? Does the Yellow wire need to stay connected to Black during operation?
What happens to the Red wire?

Also, the POWER plug has Black, Red and Orange. What does the Orange connect to?

Appreciate any help/suggestions.



Joined Jan 27, 2019
Welcome to AAC.

This is a little hard to follow but from what I gather, you want the yellow and block on the safety switches and the others on start.