Need help with draining battery + battery light

Hey Guys,

I just got back from a road trip with some big hills. The next day driving in the city the truck died after a stop light. A few lights before that it was starting to have issues trying to accelerate and so I thought it maybe transmission issue. It completely died and when I pulled over it would not do anything when I turned the key. It then began to click and I could tell the battery was low because I accidentally hit the wipers at one point. I called AAA and they came out and said I needed a new battery so I had them replace it. Started up fine and I got going with my day. Not long after, I noticed the battery light was on and it could have been on the whole time but I just happened to notice at that point I'm not sure. Manual says to pull over and not drive. I called AAA back and a second guy came out. He says it's the alternator and the first guy should have known and not sold me a battery because this one is going to drain as well if I keep driving. I get it towed to my house, order an alternator from advance, get instructions/build confidence from tacomaworld and change the alternator myself. Battery light is still on. Call AAA again thinking that maybe it's a bad battery but guy comes out and says it's fine. His print out says "charging test 11.95v LOW" and "load on 12.1v LOW". He doesn't know what the problem is and wishes me good luck. It starts fine, it started fine with my old alternator as well. Its a 2006 double cab v6 4x4 w tow package at 60,000 miles. The old battery that was in was 24f but I put in a 27f because i read thats what you need for the tow package. Alternator is carquest 130 amp 12.5v. Any thoughts on what I should be looking at next? Im going to try and look at some of the wiring today but from what I could tell at a quick glance yesterday it was good at the alternator plug and battery.

 

This may assist you in your search for a problem.

Charging Circuit:

https://www.customtacos.com/tech.ol...6toyewd/06toypdf/ewd/2006/tacoma/h/em01d2.pdf

 

Hi,
Thanks for the link. I am a little more basic and was just going to look for a broken wire or something out of the ordinary. What will this diagram help me with and how do I use it? Thanks

 

This is showing you all of the wiring connections, where they go and what they are for. If you don't understand the schematic or if you don't have a DMM or know how to use one, it may make sense to look for assistance.

 

Wires look good, nothing visibly wrong. Tested battery with multi meter and it goes lower while idling, when revving to 2000rpm and turning on A/C. Can it be anything besides a bad alternator?

 

battery light 9/10 its alternator...

 

Start checking the cables to your alternator and battery and vehicle grounds for corrosion. I would start there.

 

No corrosion on the wires. Cables look good from what I can see without unwrapping them. Is there more then one grounding spot? There is a nut right near the battery to the side metal and it looks good. Maybe I could take it off and clean it just to be sure. When the guy changed the battery they put some red stuff all over the terminals but I wouldn't think that would be an issue. Assume anti corrosion or something.

 

Belt is spinning

 

Start wiggling wires and see if light goes out, possibly a mouse could have chewed a wire.

 

First test the alternator again. With the engine running place your multimeter probes on the battery terminals. You should get 13 volts or higher. Have someone step on the gas and take the rpm’s up to 2000 . You should get around 14 volts or so minus or plus .2 or .3. If when revving the engine the voltage goes above 14.5 volts you may possibly have a bad voltage regulator.
Now check the alternator diode. With the engine running set your voltmeter to low a/c setting (alternating current). Touch the probes to the battery. If you detect any a/c voltage your diode is bad.
It is not unheard of for a new alternator to be bad.

 

If you installed a rebuilt alternator from Advance it is almost a given it is junk.

 

Advance, Auto Zone; O'Reilley, etc. - their alternators/starters are made in China. There was a time when Car Quest made fairly decent alts/starters, but they were bought out by Advance.

 

Look at the pdf jimmyh posted. Are those alt fuses good?

 

As above check the small fuse for the exciter circuit so alternator functions correctly.
Voltage regulator is in the alternator and can be defective so yes recheck the alternator output.
AAA should do this for you (again) or most auto stores do it for free too.

 

Thanks everyone for your input, help and even looking at this post. I am really thankful for tacomaworld. I did do the volt test again and it was never over 12.3 and just got lower. Checked wires, connections and fuses which were all fine. Did an A/C current test that I found somewhere through here and also this magnet test but can't reference or give credit because I just copy and paste into docs so I can print and take outside with me. But this was it:

Step 1
Insert the key into your car’s ignition switch. Leave it in the “off” position”. You do not need to start your car’s engine to test the alternator field current.
Step 2
Open your car’s hood and secure it. You need to access the alternator to test the field current.
Step 3
Test the alternator for magnetism. Use a metal screwdriver and place the metal end very near the bolt on the alternator pulley. It’s on the front of the alternator and the alternator belt goes round the pulley. The end of the screwdriver is not drawn towards the bolt as there isn’t any electrical magnetism.
Step 4
Turn the ignition key to the “on” position, but do not start your car. The dashboard warning lights illuminate and the voltage regulator is activated.
Repeat the test using the screwdriver. Place the metal end of the screwdriver near to the nut on the alternator pulley. You find a strong magnetic force immediately pulls the screwdriver towards it, even if the screwdriver is a reasonable distance away, if there is alternator field current. This means the alternator is operating correctly. If the screwdriver isn’t pulled towards the nut on the pulley, your alternator or voltage may not be working correctly.

I ended up buying a new carquest alternator so I can return the old one without a fight and swapped them. Everything seems fine now but will know for sure when I go for a drive to return the bad alternator. Im wondering if I should try to fix my original alternator for future use instead of getting my core deposit back. Im nervous that this car quest may not last but I needed my truck back on the road asap. Thanks again guys.

 

getting it sorted.