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Old 01-18-2012, 12:34 PM   #59 (permalink)
wstar
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Quote:
Originally Posted by ChrisSlicks View Post
Not sure that you would capture the pulses with a multimeter, they appear to be only 1ms in duration at about 75ms, 35ms, 12ms apart respectively, definitely the job for a scope.
Well what I mean is, we don't really have to capture them, since they're documented and they have to come from the BCM because there's no other way it's signaling the module to make the change.

What I don't understand is whether the lock module also supplies voltage to this wire at times to provide feedback to the BCM or something.

One way or another, a replacement would need: a cheap microcontroller to sense the command pulses on the communication line and update a little NVRAM state indicating whether the fake lock is currently stuck-on or stuck-off, the microcontroller would need to be powered on any time either of the power supply pins lights up and provide S1/S2 feedback based on NVRAM, and possibly voltage feedback on the communication line as well.
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