Intermittenly charging Alternator

Im relatively new to the 2nd gen tacoma Ive only had it about 2 months and my Battery light comes on randomly while im driving, stay on for a few seconds and cuts off. The battery and alternator both tested good and fuses are good and i just replaced the belt what else could it be, it is the 6mt 4x4 with tow package if that matters thanks guys and gals.

 

Given that both the alternator and battery tested good, I'd be looking for loose and / or dirty connections.

 

Ok thanks I’ll clean my alternator connections I already checked battery connections

 

Don't forget any main grounds.

 

Do you know where they would be located?

 

Just follow the ground cable from your battery for the main one.

 

ok i can do that thanks for the info.

 

Just because it checks good doesn’t mean it is good.
Intermittent is intermittent.
It was good when they checked it...
Go buy yourself a lighter adapter that displays voltage.
Get a nominal reading.
When the light comes on check your voltage.
Alternator can be internally bad for the light circuit.
Alternator can be internally bad intermittently for regulator etc.
Dash light circuit could be an issue also.

when problem is happening that’s when it has to be checked.


No add on crap I assume.

 

Check cables, especially the B+ connected t the alternator. if all cables are good and they are tight on the grounds could be a voltage regulator going.

 

No addons just stock atm

 

I will check it out

 

I agree with Tacoma Mike. Same problem with my daughters Jeep. As it warms up, voltage drops, recovers, etc. She noticed the headlights “ blinking” . Tested good at parts store, but, I insisted keep testing, and it failed third test.

 

if you have a meter hook it up and push the connector at the Alt hard in various directions - look for voltage changes/drops. Just replaced a bad connector on an F-150 this weekend for that exact reason.

 

I get the impression that alternators fail pretty regularly on these trucks. Is there a common mileage where one could expect issues?

 

Not really. Denso makes pretty good alternators. Mine lasted 23 years

 

Most alternator issues in TW are from water and mud, not the alternator itself.

 

Would applying dielectric grease to the connections reduce the risk of alternator damage? Or is it unavoidable when doing water crossings?

 

It’s a brushed motor that is open, so contacts aren’t the issue. There used to be a rebuild thread on here somewhere, I’ll try and find it.

 

@Sandman614 did a great write up, but it shows what kind of shit can get in there.

https://www.tacomaworld.com/threads/2nd-gen-1grfe-alternator-rebuild-mud-cleanout.453757/

 

especially if you're a dirty boy/girl

Just cleaning out the brushes could make a world of difference.