Dead Alternator
Thread Starter
|
Freshman User
Joined: Mar 2006
Posts: 28
Likes: 2
Dead Alternator
My '02 Explorer XLS's electrical system went out New Year's Eve after the following sequence.
1) Radio went out for approx. 5 seconds followed by a flashing ABS warning light.
2) Approximately 1 minute later, the volt meter dropped to zero charge from the alternator accompanied by a steady battery light.
3) Approximately 3 minutes later, the instrument panel goes out with dimmed headlights, but the engine remains running for approximately 1 more minute before I park it under a parking lot light and call it a night.
There was no unusual or excessive noise coming from under the hood and the alternator was not unusually hot to the touch, but this sequence of events seems to be consistent with load shedding as the system maintained power to the vital components as the battery was being expended.
Should I be looking at replacing the alternator or could there some other problem with the electrical system?
1) Radio went out for approx. 5 seconds followed by a flashing ABS warning light.
2) Approximately 1 minute later, the volt meter dropped to zero charge from the alternator accompanied by a steady battery light.
3) Approximately 3 minutes later, the instrument panel goes out with dimmed headlights, but the engine remains running for approximately 1 more minute before I park it under a parking lot light and call it a night.
There was no unusual or excessive noise coming from under the hood and the alternator was not unusually hot to the touch, but this sequence of events seems to be consistent with load shedding as the system maintained power to the vital components as the battery was being expended.
Should I be looking at replacing the alternator or could there some other problem with the electrical system?
Tuned
Joined: Aug 2010
Posts: 343
Likes: 7
From: Arizona
To test the alternator:
1. With the key turned on but the engine not running, use a digital multimeter to check the battery voltage. Then check the voltage at the alternator's positive output terminal (the big terminal, with a wire going to the battery's positive terminal) and a good ground on the engine. The two voltages should be the same; if they aren't, there's a bad connection.
2. If that tests OK, then start the engine and check battery voltage again. It should be at least one volt higher than it was before. If it isn't, replace the alternator.
Of course, if the belt is slipping or has come off (I've seen it happen) then even a good alternator won't charge the battery.
1. With the key turned on but the engine not running, use a digital multimeter to check the battery voltage. Then check the voltage at the alternator's positive output terminal (the big terminal, with a wire going to the battery's positive terminal) and a good ground on the engine. The two voltages should be the same; if they aren't, there's a bad connection.
2. If that tests OK, then start the engine and check battery voltage again. It should be at least one volt higher than it was before. If it isn't, replace the alternator.
Of course, if the belt is slipping or has come off (I've seen it happen) then even a good alternator won't charge the battery.
Postmaster
Joined: Jan 2009
Posts: 4,584
Likes: 3
From: Chesapeake, Va.
These alternators are also noted for having stuck or hung brushes. My stator was ate up on the brush rubbing surface at 140,000 miles and my MarkVIII is still soldiering on at 199,000 with the original alternator. Another not so common failure is the regulator/rectifier dies. It's available from Autozone and not very hard to replace on some models.
