I’m having a problem with a deceleration braking light. It should detect brake light activation as is wired in to circuit. However, not working. Manufacturer advises if the Breva brake system had “Pulse Width Modulation” it would cause the problem. Does anyone know if the Breva 1100 has this feature? Think it is used on some recent BMWs.
Not heard of that but it does use the cambus system which monitors the amount of power drawn and if it detects more power is drawn than should be then it shouts down that circuit which is a pain for adding on acessories which you want to come on with the ignition and not powered at all times
Helpful, thanks.
rear light on the breva is led, unit.don’t now if that makes a difrenc.
for sure the technology only exists with LED systems but it is not essential.
I’ve now tested the brake light circuit and get a 6v reading with brake light off and 11v with brake light on. The 6v suggests something going down the wires so perhaps this evidence of pwm?
So same LED’s are used for tail light and brake indication, if so (sounds like it) then I’m guessing the 6V is LED’s ‘dim’, i.e. tail light only, 11V, bright, acting as brake light.
I designed and made a similar system couple of years ago using the same principle.
So looks like what you’re trying to do, won’t work. Because there is no seperate brake light feed wire. 
Don’t know what PWM is in relation to brake lights, never heard of it before in that context.
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Appendix: could be PWM applies in that a rapid on-off switching (too fast to be visible to human eye) creates the illusiion of rear light LED’s appearing ‘dim’, for tail light function. Guessing mind you.
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