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> Green Instrument Light/Alternator, Troubleshoot
xperu
post Sep 24 2018, 02:07 PM
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My alternator light came on so before I look into a replacement, is there any troubleshooting I should do first? Thanks Mike Kelly
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TheCabinetmaker
post Sep 24 2018, 03:44 PM
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Sure. Start with the fan belt. Is it there? Is is tight!
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Spoke
post Sep 24 2018, 04:05 PM
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As stated, check the belt first.

If the belt is ok and tight, do the following 4 voltage measurements with the engine running at idle:

1) Battery voltage from battery terminal POS to chassis (not battery negative)
2) On the voltage regulator plug, measure DF to chassis
3) On the voltage regulator plug, measure D+ to chassis
4) On the voltage regulator plug, measure D- to chassis
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ChrisFoley
post Sep 25 2018, 06:55 AM
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Green Light ≠ Alternator
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bigaadams
post Sep 25 2018, 07:51 AM
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QUOTE(Spoke @ Sep 24 2018, 04:05 PM) *

As stated, check the belt first.

If the belt is ok and tight, do the following 4 voltage measurements with the engine running at idle:

1) Battery voltage from battery terminal POS to chassis (not battery negative)
2) On the voltage regulator plug, measure DF to chassis
3) On the voltage regulator plug, measure D+ to chassis
4) On the voltage regulator plug, measure D- to chassis



Perhaps you could go a step farther and explain to the poster what voltages are to be expected at each reading point you have posted....and the cause (suspected problem) if voltages fall outside this range.
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ChrisFoley
post Sep 25 2018, 08:25 AM
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QUOTE(xperu @ Sep 24 2018, 04:07 PM) *

is there any troubleshooting I should do first?

Check your oil level?
If the red light comes on when you turn the key to the "Run" position and then goes off after the engine starts there is nothing wrong with your alternator.
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GregAmy
post Sep 25 2018, 08:55 AM
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QUOTE(ChrisFoley @ Sep 25 2018, 08:55 AM) *

Green Light ≠ Alternator

+1.

Always bothered be that they used RED as the indicator for low voltage and GREEN as the indicator for no oil pressure. At worst, it should be the other way around...
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xperu
post Sep 25 2018, 02:33 PM
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QUOTE(GregAmy @ Sep 25 2018, 09:55 AM) *

QUOTE(ChrisFoley @ Sep 25 2018, 08:55 AM) *

Green Light ≠ Alternator

+1.

Always bothered be that they used RED as the indicator for low voltage and GREEN as the indicator for no oil pressure. At worst, it should be the other way around...

My mistake, thought the green was for the alternator. I read the owners manuL wrongly thanks for the help Chris and everyone. Mike Kelly
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xperu
post Sep 25 2018, 02:58 PM
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QUOTE(GregAmy @ Sep 25 2018, 09:55 AM) *

QUOTE(ChrisFoley @ Sep 25 2018, 08:55 AM) *

Green Light ≠ Alternator

+1.

Always bothered be that they used RED as the indicator for low voltage and GREEN as the indicator for no oil pressure. At worst, it should be the other way around...

Why I read the manual wrong, it's a little confusing at first glance. Please see link
http://www.914world.com/bbs2/index.php?aut...ch&id=10188
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GregAmy
post Sep 25 2018, 06:33 PM
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Soooo....which lamp is lit?
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xperu
post Sep 25 2018, 07:01 PM
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QUOTE(GregAmy @ Sep 25 2018, 07:33 PM) *

Soooo....which lamp is lit?

The green lamp, the manual shows oil on the left and the green lamp on the right. See the multi-gage.
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GregAmy
post Sep 25 2018, 08:09 PM
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Ok, I may be silly but I'm definitely still confused.

Is the lit lamp the one with the big word "OIL" above it, or the other one below the "G" surrounded by a circle? Or is it the big "B" with a circle around it?

And is the engine making bangy-bangy noises when you run it?

And have you checked your oil level? And have you checked battery voltage via a VOM with the car running?


To be more clear...if the lit lamp is the one on the "right" and it's green...then you have an engine oil pressure problem and/or an engine oil pressure indication problem. Don't drive the car until you resolve it.

1974 combo gauge if you do not have center console:
http://www.p914.com/p914_gauges_combo-74_front.htm

(IMG:http://www.914world.com/bbs2/uploads_offsite/www.p914.com-15565-1537927945.1.jpg)

1974 fuel gauge if you do have a center console:
http://www.p914.com/p914_gauges_fuel-74_front.htm

(IMG:http://www.914world.com/bbs2/uploads_offsite/www.p914.com-15565-1537928140.1.jpg)
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xperu
post Sep 25 2018, 08:44 PM
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It’s not a problem Chris, I looked at the detail in the manual /link and saw the Oil indicator on the left side of the gage. The green light the left thinking it was the alternator based on the drawing. Not a problem, I understand. Mike
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Tbrown4x4
post Sep 26 2018, 02:58 AM
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Just noticed this warning under the illustration you linked:

"The illustration depicts the fuel gauge used in 1972 and is incorrect for the 1973 model year."

Maybe the 74 manual also used that picture?
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Front yard mechanic
post Sep 26 2018, 06:26 AM
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What should I do I'm color blind (IMG:style_emoticons/default/shades.gif)
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ChrisFoley
post Sep 26 2018, 07:31 AM
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QUOTE(Front yard mechanic @ Sep 26 2018, 08:26 AM) *

What should I do I'm color blind (IMG:style_emoticons/default/shades.gif)

read the label (IMG:style_emoticons/default/slap.gif)
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GregAmy
post Sep 26 2018, 07:40 AM
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Many moons ago one of the dealership techs pulled a prank on the guy in the next bay by swapping lamps in the combo gauge and disconnected the alternator. Drove the other tech crazy as he tried to troubleshoot a persistent oil pressure problem...
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xperu
post Sep 26 2018, 01:19 PM
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QUOTE(Tbrown4x4 @ Sep 26 2018, 03:58 AM) *

Just noticed this warning under the illustration you linked:

"The illustration depicts the fuel gauge used in 1972 and is incorrect for the 1973 model year."

Maybe the 74 manual also used that picture?

Great, thank you for opening the link I provided; you may the only one, and yes it is incorrect for a 74. Tis was why I was confused in the beginning.
I went to my Haynes manual to see what it would take to replace my oil pump. In doing so, I discovered that my oil pressure switch wire had came off the switch. Reconnected and all is good. Thanks everyone for your input. Mike Kelly
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xperu
post Sep 26 2018, 01:24 PM
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QUOTE(Tbrown4x4 @ Sep 26 2018, 03:58 AM) *

Just noticed this warning under the illustration you linked:

"The illustration depicts the fuel gauge used in 1972 and is incorrect for the 1973 model year."

Maybe the 74 manual also used that picture?

Great, thank you for opening the link I provided; you may the only one, and yes it is incorrect for a 74. This was why I was confused in the beginning.

I went to my Haynes manual to see what it would take to replace my oil pump. In doing so, I discovered that my oil pressure switch wire had came off the switch. Reconnected and all is good. Thanks everyone for your input. Mike Kelly
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GregAmy
post Sep 26 2018, 02:18 PM
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QUOTE(xperu @ Sep 26 2018, 03:24 PM) *

Great, thank you for opening the link I provided; you may the only one, and yes it is incorrect for a 74. This was why I was confused in the beginning.

I think everyone opened the link - I certainly did - and we all went "what in the hell are you talking about", and confusing all of us.

And I see you edited your original post where you said it was the green light on and then asking for alternator help, when we all knew the green one is for oil pressure.

Sorry to come across as a dick, but you really made this really, really hard for anyone to help you. But at least it was entertaining.

BTW, the tech figured out someone was screwing with him when he took the wire off the oil pressure sensor and grounded it to the engine tin and saw that the alternator light was illuminated.

Kinda ironic, if you ask me...

Ciao!
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