Alternator not charging

I have a 2006 Toyota Tacoma. 4.0 liter v6. I have replace the alternator with 3 refurbished alternators before I bought a brand new one. The first alternator did not put out voltage. The second alternator put out surges to 18 volts. And the 3rd refurbished alternator did not put out voltage. Now my brand new alternator is not putting out voltage. If I take the negative terminal off the battery the car dies. I have tried cleaning all of the ground connections I can see. I have checked all the fuses related. If I take the positive cable off the alternator I am not reading any voltage. The harness the connects to the alternator only has 1 pin that has voltage when the key is in the on position and it reads 10.5v.

 

Buy a quality alternator, not a refurbished piece of rubbish. Seen that happen many a times on aftermarket ones they are hit or miss. Make sure your battery is fully charged, an alternator will not charge a dead battery.

 

10/4 ended up going with new alternator and also put a new battery in.

 

Those stores like autozone and the like, enjoy selling you a starter or alternator with a "lifetime warranty". Now if those parts didn't leave you stranded, it might be worth the chance, otherwise I'd just buy something of better value. Reminds me of this quote

 

Please don't "test" the alternator by disconnecting the battery with the engine running, it's not a good test and the voltage spike can fry things in your electrical system. Buy a cheap multi-meter and use that, system voltage should be 13-14.5 volts with the engine running depending on ambient and engine temperature

 

These are handy to have if you are having alternator/ battery issues. They show the battery charge with the key in ON position, and alternator output when running.