My alternator sensor keeps flicker while I'm driving. When the car is on park idling it flickers. Why does this keep happening and what can i do to fix it?
Ur altenator or regulator may be going south. I wud put a voltmeter at the battery and see how much voltage it registers. If ur not arnd 14volts w/ engine running -- it's likely one/both of them malfunctioning. If u don't have a meter - can always go to AZ and have them test it...
It could also be a loose bulb on the indicator light. If it happens like say particularly when you are on a bumpy road, check for corroded contacts and loose bulbs. If it happens more like when you are accelerating or decelerating that is more likely to be a loose belt because RPM changes will cause the belt to slip. If it is just truly intermittent, likely a failing alternator or failing VR.
The light should not be coming on while the engine is running, even if bulb is loose... I'd check for loose connections on the alt and regulator also their mounting... As mentioned alt should maintain around 14v when charging with engine approx 2K RPMs...
The bulb is part of the excitation portion of the circuit, it helps provide the reference voltage. If the bulb is loose and breaking contact it will cause the field to collapse and the bulb to turn on briefly when it regains contact. And he said it FLICKERS which to me this could be a cause of FLICKERING. I've fixed a few flickering indicator lights this way. It could also be loose wires on the battery itself. or loose wires between the alt and the indicator light. Flickering is usually a loose connection somewhere, being exacerbated by vibration or bumping while driving. Please continue to argue with me if you would like. I am just suggesting one alternative, much as the other people ahead of me did. This is also a trick I was taught to employ when trying to diagnose resonant frequency issues in my machinery, set a warning light a little bit loose and watch for it to start flickering. I gotta stop coming back and editing this... I am straying far off topic.
If you'd check the actual circuit, there is a parallel resistor that acts to excite the alt, even if the bulb were loose, blown or tossed out the window...
Oh damn your right, I guess that's why you have to put in a 333 ohm bypass resistor instead of just leaving in that 150 ohm one. It doesn't matter if the bulb is in the circuit or not. I guess reference voltage for the field can really be just any voltage and not a specific one. edit- the non snarky answer is that resistance in parallel is additive so the resistor on its own doesn't provide the correct reference voltage.
