Alternator Light flickering

[enjr44]

You can be a parts changer or you can do a proper diagnostic. It could be a bad battery. Just because its new dont mean sqwat.

Two things. One he did take it to a proper shop and it was the alternator.

Two, I don't think a modern charging system works that way. The light is hooked to the battery positive on one side and the alternator on the other. With key in run and the engine off, 12 volts from the battery goes through the light and to the alternator and it lights.

With the engine running the alternator also puts 12/13 volts on the wire going to the light. With 12 volts on each side of the light, it will not light. Very simple and very effective. A flickering light usually means one of the three windings in the alternator is not working causing the voltage drop across the lamp one third of the time. At higher rpms, the drop is still there, but is too fast to see.

The battery would have to be almost shorted to ground (dead) to get the light to light and then the truck would not start.

 

[delaware74b]

I had the original alternator go bad on my '04, similar situation. Battery light on at idle until hit 1500-2000 rpm. The brushes were worn down, diodes and regulator were fine. I replaced the brush set and it lasted another 65K miles until the slip rings wore through. Ended up getting a so-called lifetime replacement for $145. Turns out it's actually a limited lifetime warranty. If they have to replace it, the replacement has only a 90-day warranty. WTF?! The replacement went bad, no charging at idle, no idiot light coming on and battery kept dying. I said f it. Bought a NEW alternator and battery at N**a. Full lifetime warranty with roadside assistance (up to $65 per incident) for $15 more than the reman unit. No brainer decision.

 

[Andy D]

The 90 amp Bosch in my 528e will not start charging until I blip the throttle to get the RPM past 1100 RPM. Just a tap and the light goes out and stays out at an idle The alternator is regulated to 14.1 volts. I replaced the brush/regulator and a bearing and it was charging just fine at 350K when I retired the car. Apples and oranges maybe. But I would be checking what is going on with a voltmeter before . I'm sure your mechanic/ ex crew chief will treat you right. I'm a 64 yr old creaky kid. and after nearly 50 yrs of DIY shade tree fixing, I have decided to let a local Valvoline franchise. change the oil on MDW's '09 Camry. I am probably going to have a local shop do the fixing on it as well. It hasn't needed anything but a couple oil changes so far.