Is my alternator stuffed? - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

MickyB · 08-12-2003, 19:11

The other night I was dropping back a video and turned my ignition off and took my keys but forgot to turn off my headlights. As I was only out of the car for a maximum of 30 seconds I thought the car would be fine.
When I got back in, the car started fine but the battery warning light stayed on. So I turned my stereo off and it still flickered, and only turned off when I switched the headlights off and left the car running once I got home. Now the light stays off during the day, but as soon as the headlights come on, the bloody light comes straight on. I can't hear any belt slippage and I own a multimeter but am unsure of what to look for with it.
Any help would be greatly appreciated as I am not in the mood for my car not starting after work one night!

cs123 · 08-12-2003, 20:37

With the engine running put the meter across the battery, rev the engine to 2000 RPM. It should read around 14V.

Dellboy999 · 08-12-2003, 21:42

check fan belt tension for the alternator for one thing, mine was not tight enough, and I eventually gave myself a flat battery, but no light came on in the dash, so best I can guess i was supplying enough current to run things but not enough to charge the battery, so the light never came on, tightened the fan belt and all is ok now.

Dellboy999

Extreme_2020 · 08-13-2003, 02:36

Could be the voltage regulator for the alternator....im not too sure if the EB alternator has an internal or externally mounted regulator...have a look behind the actual alternator itself...if you see a black box and two screws then thats the regulator...pull it out and have a look a the length of the brushes...if they are very low then buy a new one only about $25 or so...

Also do what others said and check with multimetre over terminals and fan belt tension first...if they check out then have a look at the regulator :-)

Extreme

MickyB · 08-13-2003, 15:17

I checked voltage across the battery, about 12.6 with ignition off, drops to about 12.3 when the engine is running, could this be a dodgy battery, or most like alternator problem? I will check check fan belt today, thanks guys

Sundeep · 08-13-2003, 17:51

If you need an alternator you know who to PM :s5

Sundeep

NZ · 08-13-2003, 20:16

Mines cheaper

cs123 · 08-13-2003, 20:32

Quote:

Originally Posted by fordskick

I checked voltage across the battery, about 12.6 with ignition off, drops to about 12.3 when the engine is running, could this be a dodgy battery, or most like alternator problem? I will check check fan belt today, thanks guys

That will be an alternator, more than likely the regulator or brush assembly. You can remove and inspect the brushes to check for wear.

Brushes are easily replaced if you have a soldering iron. Regulators are a bit more expensive. It may be a good idea to take it to a auto electrician for diagnosis and quote.

I wrote a very basic article on this that is here
http://www.ford-tech.com/articles.php?articleId=16

MickyB · 08-14-2003, 21:20

Stupid me found out the problem: the wire running from the alternator to the positive on the battery had become dislodged from the alternator. It was touching the alternator periodically, but never in contact enough to charge the battery, or lift the voltage. After fixing this the voltage across the battery is around 14.1-14.3 so I am happy. Thanks to all for helping

TopGhia · 08-15-2003, 01:24

Ah, the old "loose wire" trick :)

cs123
Thats a good article, good tips.

cheers