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Alternator light comes on - car dies
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LORRIE THE LEO
New User
Mar 25, 2012, 5:45 PM
Post #1 of 8
(2484 views)
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Alternator light comes on - car dies
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I drive an 84 Lincoln Town Car. A while back the car's alternator light came on while I was driving to work. I asked a mechanic what this was about and was told it was nothing. However, the next morning while driving to work, in the dark, the car just died. With another person's help we pushed the car into my company's parking lot. I called the mechanic to come help me. He said the car started right up for him so didn't know what could be wrong. The alternator light came on while driving to work that morning, I again mentioned this to the mechanic. He couldn't tell me what the problem was. He was right. When I went home that afternoon the car got me home and the alternator light did not come on. However, that evening while driving to the store, the alternator light came on and I was driving with the lights on again, the car died at a stop light. The local police pushed me into a vacant lot. I called the mechanic, he came, jump started the car, I told him that the lights were what was draining the car. He verified that, so we took the car to my home. The car would run okay for awhile but got to the point when the alternator light came on it would die. I eventually replaced the alternator and starter solenoid upon his recommendation. The alternator light continued to light up and die. The mechanic had me replace the battery. The alternator continued to light up and then die. So the mechanic took it and replaced the whole charging system. In addition to that he replaced the freeze plugs, the a-arms, shocks and exhaust system. The alternator light continued to light up and the charge would be lost. He replaced the alternator, however, the alternator light still lights up and all charge is lost. The mechanic has thrown up his hands in frustration. However, the original problem still exists. The alternator light still continues to light up and the car dies and requires a jump start. Can you help?
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Discretesignals
Ultimate Carjunky
/ Moderator
Mar 25, 2012, 6:09 PM
Post #2 of 8
(2457 views)
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Re: Alternator light comes on - car dies
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Didn't your mechanic bothering checking the circuits to the alternator before condemning it and rebuilding the system, what ever that means.
This alternator is externally regulated. The easiest way to check the alternator itself is to make sure that you have battery voltage to the alternator and the alternator is grounded. Make sure your engine ground is clean and tight. Full field the alternator, with the engine running, by jumping battery power to the field terminal for a few seconds. You should see charging voltage go up with your meter connect at the battery. That means the alternator is good and the external regulator is not controlling the field power side of the circuit for some reason. From there you would check for power from the ignition switch and battery, stator sense circuit, and ground circuit at the regulator to determine if the regulator is the fault.
Check the alternator ground with the engine running and everything turned on using a voltage meter. Touch the alternator case and touch the other probe to the battery negative. You see more than .3-.5 volts, you have a ground problem.
Something is going to be missing when you check all those things when the problem is occurring. Just throwing parts at doesn't always solve your problem.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
(This post was edited by Discretesignals on Mar 25, 2012, 6:17 PM)
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nickwarner
Veteran
/ Moderator
Mar 25, 2012, 6:17 PM
Post #3 of 8
(2452 views)
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Re: Alternator light comes on - car dies
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Have you had the alternator load tested by someone other than this guy? Go you have shiny clean and tight power and ground hookups? Have you tested the fusible links to see if the alternator field coils are getting a voltage signal? You said after he replaced the battery, starting solenoid and alternator, and THEN he later replaced the entire charging system. Hate to tell you, but I would want to know what other parts he considers the whole charging system. After you already had a new alternator and battery, a few wires is all thats left in the charging system. What is the system voltage at when the light comes on? How many amps is your alternator rated for and how many is it CURRENTLY making. I stress this because even new ones can be duds out of the box.
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LORRIE THE LEO
New User
Mar 26, 2012, 5:34 PM
Post #5 of 8
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Re: Alternator light comes on - car dies
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Okay, the mechanic says he's done all this except run a wire from the battery to the alternator and everything tested alright.
Any other suggestions?
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LORRIE THE LEO
New User
Mar 26, 2012, 5:36 PM
Post #6 of 8
(2409 views)
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Re: Alternator light comes on - car dies
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Okay, the mechanic says that he's tested all this stuff except for running a wire from the battery to the alternator.
Any other suggestions?
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nickwarner
Veteran
/ Moderator
Mar 26, 2012, 6:44 PM
Post #7 of 8
(2401 views)
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Re: Alternator light comes on - car dies
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Has he bothered to do a voltage drop test on this wire? I sounds like he's in over his head and his knowledge of electrical systems isn't up to par. Seems he just throws parts at it. Thats an expensive way to fix things.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Mar 31, 2012, 7:24 AM
Post #8 of 8
(2364 views)
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Re: Alternator light comes on - car dies
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The plug right at alternator was a common problem on these and could be the problem. New plug for those are available to solder in if that's it. They used to burn with the common failure,
T
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