Repair Topics / Charging System-1 / Charging System-2
 
Charging System Questions and Answers

This category contains featured questions as examples. They relate to most vehicles.

Question: 1998 Mercury Mystique V6 mileage: 56,950. My Charging System light is on. Not fully lit, but dim and flashing. My Battery was completely dead, so I bought a new one. The Light is still on. When I start the car and pull off the positive and negative poles to test the alternator the car instantly shuts off. The problem is I can't find the alternator to replace it. My Question is the alternator gone bad or what is making that light come on.

Answer: Do not remove the battery cables with the engine running. This is not the way to test an alternator. There are special instruments for load testing an alternator. Without checking your car, we suspect that you have a burned out diode in the alternator, which would require replacing the alternator.

Question: 1998 Chevy Geo Prism mileage: 82,000. The battery charging light came on, so we took it in to a shop and had the battery changed. The light stayed on. We then took it in to the dealer and they put in a rebuilt alternator. That was three months ago. Today, the battery light came on again, and the power steering has become really tight. Is it possible that some other part of the electrical charging system may be the problem? If so, what?

Answer: First thing to check would be the drive belt. Make sure that it is tensioned properly and not slipping. Next, check the alternator output.

Question: 1999 Ford Taurus mileage: 35,000. We have replaced the alternator 3 times this week and none of the replacement alternators has been good! Is there a problem other than the alternator that could be causing the replacements to fail as soon as they are installed? I have checked the output voltage with the car at idle and the voltage is 0. (Checked with lead to alternator disconnected.)

Answer: This is a classic example of what happens when a budget alternator is installed. Make sure only top quality replacement parts are installed. Sometimes these parts cost a little more but to avoid frustration it is worth it. Get a top quality alternator for your replacement.

Question: 1999 Chevy 3500 6.5L diesel mileage: 80,000. Charging system is unable to handle loads (night driving specifically). Will not provide 14 volts with headlights on. New alternator and both batteries. Any idea what might be wrong? Is there a fuse wire in the supply side of the alternator?

Answer: Your problems may be caused by poor ground connections or improper belt tension. Also, have the alternator "bench-tested" to be sure that it is working properly.

Question: 1998 Mercury Grand Marquis mileage: 160,000.  Refresh my memory a bit; forgot how to check if my alternator itself is ok.  Alternator currently in vehicle was rebuilt and boosted to 100 amps instead of the normal 65-70-amp type.  Your response would be greatly appreciated.  Thank you.

Answer: Assuming the battery in your car is in good condition, you can check the alternator by having the engine on a fast idle with the headlights and the air-conditioner on.  The voltage across the battery should be 14 to 14 ½ volts.

Answer: We have found that the voltmeter gauge on the dash is not very accurate.  With the proper equipment, test the voltage across the battery with the engine on fast idle.  The voltage should read between fourteen and fifteen volts.   If it reads higher or lower, check for loose or bad ground connections from the engine to the battery.  If okay, your voltage regulator in the alternator may be faulty.

Question: 1999 Infiniti J30 mileage: 39,500.  After reading your answers regarding battery drain, it certainly seems feasible that this is certainly the problem I am having with my J30.  I have had the car towed to the dealer at least three times and he assures me that they have checked everything they can.  They recharged the battery and after a period of a month and a half, it starts all over again.  I picked it up again today and the report read--after charging battery completely performed extensive tests on charging and starting system.  Found no draw in system and found no reason for battery to go dead at this time.  Cannot recommend any repairs at this time.  The first time it was brought in they replaced the control unit--hybrid.  Well, it certainly did not solve the problem.  I would appreciate any help you could possibly provide.

  Answer:   After reading your question and discussing it, we feel your battery may be faulty.  A load-test of the battery may or may not determine that your battery is defective.  If it fails the load test it is obviously your battery and if it load test okay, it still may be the battery.  The reason for this is that an internal short may or may not show up with a load test.

Question: 1999 Plymouth Neon SOHC mileage: 81,000.  When I started my car today the lights are dim, but my car still started. On the drive to work, when I was stopped at a light the idle was rough and my battery light came on.  I still got to work, luckily.  However, when I went to start it again after work it took a few seconds for the radio to come on.  However, my car would not start and my lights were extremely dim.   When I got a jump I got home fine, but my lights flickered all the way home even when I pressed on the gas.  Now it will not start without a jump.  What is my problem PLEASE HELP.  Thanks

Answer:   From what you tell us, it sounds like you may be having trouble with your charging system.  Have your battery load tested and check the alternator output for voltage and amperage.

Question: 1998 Ford Ranger mileage: 129,000.  A few weeks ago, my charge light started coming on intermittently, and my battery has since died. The alternator is putting out (the exact amps I do not know).  I found this out using some shade tree methods (removing cables while engine is running, feeling magnetic pull on back of alternator).  I have since replaced the battery, and the charge light still comes on, however it stops glowing at idle with the headlamps on.  It will appear again upon acceleration.  Any ideas?

Answer:   From what you tell us, it sounds like you may be having trouble with your charging system.  Have your battery load tested and check the alternator output for voltage and amperage. Never remove the battery cables when the engine is running.

Question: 2004 Ford  F150 mileage: 65,000.  I have a problem.  I think it is my alternator, but I am a little unsure.  Periodically, my lights dim and everything electrical will slow (ac, heater, etc.).  After a short period, they will return to normal.  At first I thought it might be a short, but it does not occur when I hit a bump nor does it go away on bumpy roads (once it stopped while sitting still).  The last time it happened, my truck stalled when I stopped.  It wouldn't restart.  Then, about an hour later, it started as if nothing was wrong.  Any ideas?  I'm lost.

Answer:  Here are some things to check.  Load test the battery.  Check that the battery cable connections are clean.  Check for 12 volts to starter solenoid with the key in the start position.  These things should be checked first then the ignition switch, starter and starter solenoid.  One of these may be faulty.

Question: 1998 Ford Windstar 2.8L mileage: 85,000.  My Windstar runs on just battery power.  I have changed the alternator and checked all of the wires.  It will run for about 5 miles on a fully charged battery before the battery is completely drained.  Do you have any suggestions?

Answer:   Your definitely having some problems with the charging circuit.  Check the alternator output for voltage and amperage.  Also, check the main power wire from the alternator to the battery.  Check your electrical system for electrical drains.

Question: 1998 Ford Escort mileage: 90,000.  The battery light suddenly came on and a DVM reading on the battery showed 13.5V not running and slowly drops to 12.3V when the engine is running.  I believe the alternator is not charging.  However, before I buy a rebuilt alternator could it be something else?

Answer:   Before you buy another alternator, check present alternator for voltage and amperage output.  In addition, load test the battery.

Answer: The alternators you have been using may be of poor quality. If the diodes "bleed" a little A.C. voltage, it will shorten the life of the battery. Hearing static and engine noise on your speakers with the stereo off may indicate a wiring problem with the stereo installation. It also could cause your battery drain when the car is not driven for several days.

Question: 2002 Dodge Stratus, mileage: 70,000. Hi, my alternator over charges- periodically it puts out about 18 V and I can hear the battery sizzling. 1. I have swapped out the alternator- makes no difference (so the alternator is not the problem). 2. I have swapped out the battery- makes no difference. 3. Last Dec. I replace the computer so I would like to think this is not the problem. 4. I have checked the wiring harness. Any ideas?

Answer: Your problem may be simple like a loose or poor ground wire. If ok replace the alternator.

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