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Registered
Join Date: Nov 2004
Location: Stanley, Victoria,Australia
Posts: 245
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Connected battery the wrong way
:Ok, a friend of mine just rang and said that he just connected his battery the wrong way round.
It's a 1977 911S. It made sparks. He said he could smell that burnt electrical smell in the engine bay. He corrected his mistake but says it starts and runs fine now but the alternator light stays on. Even when the car is off and the key is out. How much damage has he done?? Cheers, Frank
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76 911S Land Rover 110 Defender |
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09-07-2021, 06:26 PM
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Registered
Join Date: Jul 2001
Location: Lawrenceville GA 30045
Posts: 7,377
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Maybe trashed diodes in the alternator/regulator?
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Mark '83 SC Targa - since 5/5/2001 '06 911 S Aerokit - from 5/2/2016 to 11/14/2018 '11 911 S w/PDK - from 7/2/2021 to ??? |
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09-07-2021, 07:15 PM
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Registered
Join Date: May 2002
Location: Portland, Oregon
Posts: 12,650
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Quote:
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Harry 1970 VW Sunroof Bus - "The Magic Bus" 1971 Jaguar XKE 2+2 V12 Coupe - {insert name here} 1973.5 911T Targa - "Smokey" 2020 MB E350 4Matic |
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09-08-2021, 09:07 AM
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It's a 914 ...
Join Date: Jan 2008
Location: Ossining, NY
Posts: 4,703
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The above is probably correct, but before pulling the alternator it's easy enough to check whether the it's working - just measure battery voltage with engine running. Not sure I'd trust the alternator light to be working correctly given the reversed polarity incident.
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09-08-2021, 02:20 PM
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John W
Join Date: Mar 2009
Location: Albuquerque
Posts: 273
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Yep. measure the voltage then you’ll know the alternator’s status.
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09-08-2021, 02:45 PM
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ROW '78 911 Targa
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Odds are a diode has fried in the alternator as current flow is being shown at the lamp with the key out.
Hopefully just flowing up the blue wire via the alternator bad diode and finding a ground through one of the instruments or gauges, as normally the balancing 12 vdc to the lamp is switched off with key out and the blue wire sees no voltage until the alternator spins. Probably should inspect the red/black wiring at the gauges.
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Dennis Euro 1978 SC Targa, SSI's, Dansk 2/1, PMO ITBs, Electric A/C Need a New Wiring Harness? PM or e-mail me. Search for "harnesses" in the classifieds. Last edited by timmy2; 09-08-2021 at 03:15 PM.. |
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09-08-2021, 03:13 PM
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Registered
Join Date: Nov 2004
Location: Stanley, Victoria,Australia
Posts: 245
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Thank you for the information and advice.
I'm going around to his place shortly to remove it. He tells me that he is taking it (the alternator) to an Auto elec to have tested and rebuilt Thank you timmy2 for the gauge wiring inspection tip. Cheers, Frank
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76 911S Land Rover 110 Defender |
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09-08-2021, 03:23 PM
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ROW '78 911 Targa
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Dennis Euro 1978 SC Targa, SSI's, Dansk 2/1, PMO ITBs, Electric A/C Need a New Wiring Harness? PM or e-mail me. Search for "harnesses" in the classifieds. |
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09-08-2021, 03:40 PM
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Registered
Join Date: Nov 2004
Location: Stanley, Victoria,Australia
Posts: 245
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I haven't looked at the dash yet but melted solder fell from the alternator when we got it out.
Here is a pic of one of the diode posts gone. And , the regulator? Been consumed by mice. Bothell are going to an auto electrician today. Thank you for the assistance.  
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09-08-2021, 04:58 PM
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Registered
Join Date: Dec 2014
Posts: 13,860
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How come it’s always are “ friends” that do stupid ****?
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09-09-2021, 04:21 AM
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Registered
Join Date: Nov 2004
Location: Stanley, Victoria,Australia
Posts: 245
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Quote:
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09-09-2021, 04:26 AM
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Heinz
