Lebowski Posted September 30, 2012 Report Share Posted September 30, 2012 OK, since the recirculation in this car doesn't work, and dodge/chrysler/fiat won't fix it (it's not a bug, it's a feature!), I want to bypass the car and control directly the servo that engages the recirculation. It's located behind the glove box, on the right side of the fan. Unfortunately I don't have an oscilloscope, so I hooked up a digital multimeter to the connector of the servo. What I can see is just a short positive pulse to move the servo in one direction and a negative pulse to move it in the other one, but I couldn't see neither the amplitude (most probably 12V) nor the duration of it. It could also be a canbus connector, but I doubt it (due to clearly seeing a positive/negative pulse). I will see if I can borrow an oscilloscope at work, but does anyone know the characteristics of this signal (i.e, amplitude, timing, etc.) ? Quote Link to comment Share on other sites More sharing options...
Moparman Posted September 30, 2012 Report Share Posted September 30, 2012 Its a 12v DC servo motor. Its doesn't get run by duration, it uses a learned current ramp, or rise. When it sees that rise( door against stop) it uses that as the learned value. Lebowski 1 Quote Link to comment Share on other sites More sharing options...
Lebowski Posted September 30, 2012 Author Report Share Posted September 30, 2012 Yes, I found it, before the probes didn't make good contact, now I see that there's a fixed 12V (or -12V in the reverse direction) and the voltage is no longer applied as soon as the current raises. Thank you. Quote Link to comment Share on other sites More sharing options...
Moparman Posted September 30, 2012 Report Share Posted September 30, 2012 Be careful, these motors are strong, and will break the door if overdriven. Make sure current is cut quick when it starts to rise , or you'll be pulling the dash to repalce a broken door Quote Link to comment Share on other sites More sharing options...
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