JDMSteven

So I'm pretty sure my alternator is on it's way out However I am at 144k so it's not that upsetting however it's a little sooner than I'd like. A manufactured 80 amp runs $119 with a $26 core so its not too bad.

I've read around that charging the battery is a good idea before starting with the new alternator as it can put stress on a new alternator, trying to charge a dead battery. Can I do this with the battery out and connect it with jumper leads to my truck (engine running)?

Also, if anyone could point me to a DIY guide that would be really helpful, if not, is there anything difficult or something to look out for? Can I use a DIY from the same gen of Camry V6?

BDSL

Make sure you disconnect the battery when replacing the alternator. You don't want to blow the 120amp main fuse by accident.....no fun.

JDMSteven

Yeah I know lol, not my first alternator job. Thing is, I have this battery and alternator tester and it indicates a healthy and fully charged battery, but it does not see power from the alternator AT IDLE. If I even barely revv the engine the green alternator light comes on, meaning its charging. This green light is supposed to be on even at idle because I've tested my gauge on two other vehicles.

HomerJay

Why do you think your alternator is bad? You need to check voltage readings with a multi-meter. I do not know what tool you are using but the best way to check if a battery is good is load testing. A battery may be fully charged but still have a bad cell(s)

JDMSteven

Yeah it makes sense. I'm gonna take it to autozone and get it tested but the battery was just put in there December.

HomerJay

Also check your terminals make sure they're clean and tight. It's still not clear what your exact problem is.

JDMSteven

Yeah I took everything out, cleaned it, made sure everything was good and put it back together

ES300NZ

Throw that crappy tester away and learn how to use a multi-meter, it's a basic auto-electrical tool.


Alternators have four wires generally,

A huge one, the output,
a charge light (negative), for the light on the dash, which is on, when the alternator is off, OR when it's 'half charging, which is a technical term for a current output less than 13.8 volts. Its a common misconception that cars run on 12, or 24 volts, they actually run on between 12.5, and 13.8 volts.
a winding exciter, which assists in power generation (constant supply),
a on/off supply, which turns the regulator on, it comes on when the ignition is turned to the second position (run).

very boring, but basically, if the alternator is off, it won't charge the battery and all manner of things shut down, and weird stuff happens. If your car at idle has less than 12.5 volts at the battery terminals, then the alternator isn't running (or is half charging), get a volt meter, test it, see what you find. Sometimes, it's good to test the battery (voltage) with the car off, then again when it's running. and see what you find.

Typically a half charing car will put out about 10-11 volts at idle, and the battery slowly dies because of that. A non charging car will run for around 15 minutes, perhaps 20. A half charging car will run for several days but be hard to start, or refuse to start without a jump. A non charging car will often read something like 10 volts or 9 volts when not running. anything under 10 volts and the car's ecu will not turn on, because it simply can't.

mitmaks

Watch on how to diagnose alternator before you waste time and money replacing yours.
Our 1996 has nearly 200K on factory one