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Registered
Join Date: Feb 1999
Location: Chelsea , Quebec , Canada
Posts: 113
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72 Alternator/Warning light problem
Ok, I'm baffled and need some help. I have a 72 with an earlier 490 wWatt Motorola alternator and matching external voltage reg. installed. The problem is that the charge light comes on with the key removed from the ignition. I have had the alternator repaired and the VR checked and all is good. Wirng is good with good connections at both 14 pin connectros.
Looking at the wiring diagrams for the 71 vs 72 cars I notice that a diode was dropped from the 72 alternator warning light circuit. Is this the cause of my light on with no key ?. From all my research it apperas that light on with no key indicates an alternator failure, alternator repair shop says all is good after brushes,bearings replaced. Alternator is charging although voltage is high with minimal alternator load it is approx. 15.1 V. Loaded the battery voltage drops to approx. 12.8 V. Any thoughts Thanks Chris |
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07-17-2006, 07:09 PM
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Registered
Join Date: Dec 1999
Location: TX USA
Posts: 9,804
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Chris,
I believe the differences in the dash wiring you noted are associated with the brake warning lamp and handbrake-operated switch ... and not the alternator and Voltage regulator. Have you personally tested the isolation diode on the Marchal alternator? Faults in the installation of the heat sink are possible. Do you have a Haynes manual? It has specific testing and disassembly information for the early Marchal alternator.
__________________
Warren Hall, Jr. 1973 911S Targa ... 'Annie' 1968 340S Barracuda ... 'Rolling Thunder' |
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07-18-2006, 06:09 AM
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Registered
Join Date: Feb 1999
Location: Chelsea , Quebec , Canada
Posts: 113
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Warren
Looking at the wiring diagram again you are correct the diode only serves as isolation for the buzzer, it is simply connected to the alternator warning light terminal. I have the factory manuals and have gone through the testing procedure for the Motorola alternator (which is what is installed). The isolation diode heat sink test was OK so I am still at not sure. I guess I'll have to pull the alternator and go through each diode to make sure. Unless I can easily check them with the alternator in place ? Regards Chris |
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07-18-2006, 03:27 PM
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Registered
Join Date: Jul 2006
Location: Maple Ridge, BC
Posts: 484
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Chris
Did you ever solve this issue and what was the problem if so?
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JOHN 79 EURO SC "24 Years Later - The Dream Came True" |
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04-21-2007, 10:29 PM
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