Electric Brake signal tap off point. LC200 2018 (The Red Wire)

Ornea

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Nov 14, 2018
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I am using a Prodigy P3 to control the current to the electric brakes and needed to access a signal that goes positive high (12V) when the brake is applied on an LC200 Series 2018

I decided to get dirty with a multimeter and the 5 pin brake switch connector and share my results.

The RED (Pin4 in my numbering system) wire was identified as being suitable for the purposes of connecting to the PRODIGY P3 so it can detect when the brake pedal is pressed. This wire goes from 0V to 12.57V when the pedal is pressed.

Wire Pins Test summary. (Details with pics can be found at https://hackaday.io/project/162319-lc-200-series-2018-brake-switch-investigation)

1. BLACK goes from 0V to 12V when the Ignition is turned on.

2. PINK goes from 12V to 0V when the brake is pressed AND the ignition is on.

3. WHITE seems to change its resistance from 1.5ohms to 8ohms then settles at 1.6ohms when the brake is pressed.

4. RED goes from 0V to 12V when the brake pedal is pressed regardless of the state of the ignition

5. Blue always 12V
 

Icehouse

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Dec 18, 2018
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Hi There,
My autoelec tapped off the red wire in the trailer socket for the Redarc TowPro. Said it was easier to do it there as he had to run a new power wire for the brakes so it was easier to run two all the way to the plug.
 

Paddler Ed

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Aug 1, 2012
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Same as Icehouse - I took the feed from the trailer socket rather than the brake switch; just meant I ran twin core/twin sheath along the chassis to do it.

Also means there's no problems with any clever electrics in the vehicle either...
 

Ornea

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Nov 14, 2018
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Yeah, I agree. However, for me I had already had all the panels off twice before to run various cables.

I had just put everything back together before I tackled the brake switch and it was only then I discovered the situation and couldn't bring myself to pull all the panels and seat belts off again. Plus the cables I had run was making it tight to run another.

If I had my time again I would do as you suggest and run a feed from the socket.
 
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Icehouse

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Dec 18, 2018
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Just noticed if i use the manual switch on the trailer brake it does not turn on the cars brake lights. Guess this means it wont cancel cruise control either.
 
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