2002 Ford Focus, driving down road, airbag light comes on, dashlights go out, engine runs rough then quits. Restarts, goes one block, quits again.
Symptoms of a charging system problem. The charging system comprises the alternator, battery and associated wiring. If the alternator should fail to produce a sufficient or stable enough voltage for the car's electronic systems - due to a wiring short, faulty voltage regulator, or corroded electrical connector, for example - the car will run off the "reserve" in the battery for a short time until the battery is eventually depleted. (The battery itself could also contribute to the problem if it has a faulty cell or for some reason is causing the alternator to put out an excessively high voltage in an attempt to compensate.)
So a couple of quick checks: Measure the battery voltage with the car off. Yours sounds like it will be dead; the clicking while attempting to start is the starter relay not getting enough juice. Then the question becomes: Is the battery dead because of age (fails to hold a charge) or because the alternator isn't charging it? To answer this question, measure the voltage at the battery with the car running. (Jump it or substitute a known good 12V battery.) You should see 14+V. If you only see 12V or less, you're seeing only the current battery charge without any contribution from the alt.
Finally, don't assume because the alt isn't putting out anything the alt is at fault. The wiring harness and electrical connector to the back of the alt should be thoroughly examined. (The wiring connector is a known failure point on early models.) The wiring harness should obviously show no signs of burning, melting or chafing and the battery terminals should be corrosion free and tight. If the harness checks out, remove the alt and have it bench tested. Rebuilding usually gives better long term reliability than chain store bought reman units, I'm told.
Long story short, I suspect the voltage regulator in your alternator failed, the battery gave it's all trying to keep your car running, finally gave up and now you have a dead alt and a dead battery. Don't just install a new battery without doing the alternator voltage output tests.
If you're really lucky it could be as simple as loose or corroded battery terminals.
Dec 31, 2012 |
2002 Ford Focus