Montero Sport 2WD V6-3.0L SOHC (1997)
Turn Signal Lamp: Description and Operation
1. In normal operating condition
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When the ignition switch is turned to the ON position, battery positive voltage is applied through the hazard light switch to the turn-signal and
hazard flasher unit.
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When the turn-signal light switch is placed in the L.H. (or R.H.) position, Tr1 in the flasher unit turns on, causing the relay contacts in the
flasher unit to close. This causes the L.H. (or R.H.) turn-signal light and turn-signal indicator light to illuminate.
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At the same time, the capacitor is charged through R2 up to the lower limit as set by COM3.
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As soon as the capacitor is fully charged, the output from COMS is inverted, turning off Tr1. This opens the relay contacts and, as a result, the
L.H. (or R.H.) turn-signal light and turn-signal indicator light switch off.
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At the same time as Tr1 turns off, the capacitor starts discharging. As soon as the capacitor completes discharging, the COM3 output is
inverted again, causing Tr1 to turn on. This causes the L.H. (or R.H.) turn-signal light and turn-signal indicator light to illuminate.
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This sequences of operations occurs repeatedly, causing the L.H. (or R.H.) turn-signal light and turn-signal indicator light to flash on and off.
2. When one bulb is burnt
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When either one of the turn-signal light bulbs switches off, it causes the resistance of the entire light circuit to increase, resulting in a smaller
voltage drop at R1 in the flasher unit.
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This smaller voltage drop is sensed and the lower voltage limit set by COM3 is raised, thus shortening the time required by the capacitor
before it is fully charged.
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As a result, the on-off cycle of Tr1 becomes shorter with the result that the light flashes on and off more quickly.
