939010269 - 5040DB Check windscreen demister sensor operation (Automatic Air Conditioning)
Using an Examiner set to the Voltmeter mode, select a 20 Volt full scale deflection and 5 seconds, connect the black probe to the vehicle earth and the red probe on pin 3 of the mist sensor output signal, turn the key on and press the START button.The signal shown should be a set of PWM impulses with a frequency of 100 Hz and a Duty Cycle that varies between 10 and 90% as indicated in the table below.The first 100 sensor output readings should not be considered (about 1 sec). |
1. earth2. +153. not connected4. signal outputPWM% Duty Cycle = T1 / T2 where:
- T1= duration of impulse
- T2 = 1/f = 1/100 Hz = Duratation of transmission
- T2 = 10msec ± 7%