Hazard Lamp - Different Flashing Feequency
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Hazard Lamp - Different Flashing Feequency
'01E430:
Just checking if this is the way the hazard lights work. When engine is on, they flash "regularly" at even intervals, like this: dit-dat-dit-dat-dit-dat. When engine is off, they flash faster at irregular intervals, like this: dit.dat---dit.dat---dit.dat. Got it? Is that how they work normally or is there something wrong? And why are they programmed to work like that?
Just checking if this is the way the hazard lights work. When engine is on, they flash "regularly" at even intervals, like this: dit-dat-dit-dat-dit-dat. When engine is off, they flash faster at irregular intervals, like this: dit.dat---dit.dat---dit.dat. Got it? Is that how they work normally or is there something wrong? And why are they programmed to work like that?
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From: Vancouver Island, B.C. Canada
2005 smart cabrio; 2008 Mercedes-Benz B 200
voltage
Originally posted by AlBoston
our 99 ML320 does the same thing... I believe it is normal. BTW, I dont see how the voltage would vary with the engine off. 12 Volt battery is a 12 volt battery.
our 99 ML320 does the same thing... I believe it is normal. BTW, I dont see how the voltage would vary with the engine off. 12 Volt battery is a 12 volt battery.
1) with the engine off, static battery voltage is actually higher than 12 V - usually 12.6 to 12.9 V in a fully charged battery;
2) with the engine (and alternator, of course) running, the voltage would be up to 14.4 V.
Conclusion: yes, there actually is a difference between the voltage with the engine on and off, which could explain the different cadence of the hazard signal.
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From: Philadelphia area
2010 ML550, 2010 E350 4M, 1966 Corvette Convt C2
Yes, 12V battery is 12 volts, however when the engine is running the system is at about 13.75 volts as thats what the alternator puts out. The battery is actually at a bit more than 12 Volts also while not running if its fully charged.
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From: Bloomington, IN
1997 Toyota Tacoma 4x4
I don't know the reason, but here's my educated guess. Maybe the different flashing frequency with the engine off less of a power consumer than the frequency with the engine on. If you think about it, when you have the engine off and the flashers on, usually you are broken down on the side of the road, so the flashers tend to stay on for a long time. How many times have you driven past a car on the side of the road that has had the flashers on for so long the lights barely illuminate at all? I think it's designed to save a little battery power.
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From: Belgium
It is the SAM (I do not know how it is called in English, but in German it is Signalerfass- und Ansteuerungsmodul), which is a sort of ECU, that picks up the signal from the hazard light switch and makes the hazard lights flash.
I do not think that battery voltage has a direct influence on the flashing frequency for as long as it is above a certain value (e.g. 11,5 V). Maybe the flashing frequency does not change under a certain voltage but hazard light function just stops working? Mercedes says hazard lamp frequency should be 1,5 Hz (three times within two seconds).
I do not think that battery voltage has a direct influence on the flashing frequency for as long as it is above a certain value (e.g. 11,5 V). Maybe the flashing frequency does not change under a certain voltage but hazard light function just stops working? Mercedes says hazard lamp frequency should be 1,5 Hz (three times within two seconds).
