Charging light on/off

Greetings all!First off 2006 Toyota Tacoma,2,7L.Couple of days ago,charging idiot light started coming on,then going off.Voltage at battery is 12.6 with truck off.With running and all accessories on,13.6 to 13.9.(Shouldn’t this output voltage from the alternator be steady).?Yes,there’s some wire ends with mild corrosion that I cleaned up.Took to autozone,and they tested system.Said battery,starter,alternator test good.When I turn the headlights on,blow motor speed kicks down just a bit.Clock light dims,and airbag light goes out.?Tension on drive belt appears fine.Is the voltage regulator of the alternator on the way out?The heater control back lights sometimes work,then don’t.Been doing that for over a year.Pulled relay for ac compressor as it’s smoked,and I’m not replacing compressor.Did this 2 years ago.I get the flashing on the ac controller,but just hit the button till it goes off.Even though autozone checked it and it tested good,could it ne something flaky going on with alternator?Thanks for reading this novel!Any help is appreciated.

 

Voltage will vary depending on temperature (13.2-14.2) but should stay fairly steady and not drop below 13.2 with all loads on.
The alternator turns on the light by grounding the L terminal so a short to ground on that wire could theoretically turn the light on as well.
You can check voltage drop by putting on lead of your voltmeter on the B+ (big wire that's screwed on) post of the alternator and the other on the positive battery post, you should have less than 0.5 volts with all loads on and the engine running.
Do the same thing on ground side (1 lead to the alternator case the other to the ground post of the battery) should be less than 0.5 volts.

 

Thanks.I’ll test that as suggested!
Thanks for the files!
Dam fine information!Now if I can decipher them!Ha!
I’m going to do the voltage drop test on each cable as you suggested!
Thanks Dm93

 

Put a voltmeter across the battery and turn all the accessories on like headlights, blower, etc. If the charging voltage drops down to the 12 volt range the alternator is bad

 

Yes I know.I’m reading around 13.8 V,with everything on.Odd thing is it fluctuates between 13.8 to 13.6 to 14.1 with everything on.I’m going to try some voltage drop test recommended by Dm93.Thank you!

 

Well,another check revealed the voltage going between 13.8,14.0.;13:0 ,all the while the alternator is making a clicking sound?This is in fully loaded state !I replaced the alternator and I’m happy to report a steady 14.2 volts,steady ,fully loaded.It is at this time,I wish to thank each and everyone of you for your input ,advice,and especially Dm93 for the down and dirty,electrical schematics!You guys are the best!Thank you!Sorry it took me so long to reply as to the fix!

 

Nice!

Thanks for the update.

 

Not a problem, glad you got it figured out