Alternator issues

[Becker69 CO]

Well today my stock battery gave up the ghost, or so I thought... after shopping in 20 degree temps. I tried to start my truck and heard a click and then nothing.... no accessory power no door lock or power windows, nothing. I pulled the key out and hit the unlock button on the key fob and heard crazy clicking from under the hood. Called my wife, disconnected the battery, waited and the same thing... although now I had power to my glove box light, domes and radio clock power. I went up the road, got a 850 CCA battery vs. the stock 650 that'd suited me well for 7 years and 5 months and tried everything again.... same result; except now I had the "Theft" light on the dash and all lights still no accessories. I closed all the doors and heard the door chime!!! What's going on I thought! Had a neighbor jump me and got it back to the house.... on the drive my lights looked yellow at times. So I figure the alternator is gone. My battery guage on the instrument cluster registers low. I have a corroded negative battery terminal that I need to replace (that has been more of a pain than a battery terminal is worth!), and intend to get read on the output of the alternator tomorrow. Has anyone else had an alternator go bad in their Explorer? Are these symptoms normal of a bad alternator? It's so hard to know with computerized cars these days! Thanks.

 

[Jacob Dryer]

I replaced my alt when it started squeaking, so no real help on the issues your having. But it wasn't that difficult to replace.



I forget what the output is, I want to say 120 but I'm not certain.

 

[Snooze]

How clean are your connections? Is there any residue or oxidation? I have experienced bad battery issues and found out that it was simply a bad connection. A simple test can be done by rubbing the connections with sand paper to expose fresh metal. I would try it even if the connections looked clean.

 

[Martin]

I have a corroded negative battery terminal that I need to replace

That's prob your whole issue right there. Many times the cable itself will get corroded as well. You might think about replacing both cables and terminals while your at it so you won't have to deal with this again for awhile.

 

[EddieS'04]

If you have a volt meter. The altenator should put out about 14.5 volts dc at the battery. As you turn things on it should stay above 14 vdc. Make shure the battery terminals are real clean first..

 

[Richard L]

I don't necessarily think it's your Alternator. Your old battery dies, and the replacement may not have been charged, or may even be defective itself. You really can't properly test your Alternator on the car without a known good and fully charged battery.



Once you get a fully charged battery installed (and you fix your cable corrosion problem, then you can simply use a volt meter to check the battery voltage with the engine off, and then again with the engine/alternator running. You should see about 1.5 volts higher reading when the alternator is running. If not, then you probably have an alternator problem.



...Rich