Alternator wiring diagram please?

Tiny
X1LIFE1CHANCE
  • MEMBER
  • 2004 CHEVROLET SILVERADO
  • V8
  • 4WD
  • AUTOMATIC
  • 100,000 MILES
Does and where is the alternator fuse located on a 2004 Chevy z71? I need the wiring diagrams
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Monday, January 10th, 2011 AT 7:43 PM

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Tiny
KEN
  • ADMIN
Hello there, the alternator is fused by two fuses and a fusible link under the hood fuse panel, here is a wiring diagram and a guide to help you. Use a test light to check for power at the back of the alternator and each fuse. Fuse IGN SEO. and Fuse IGN E

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Here are the fuse locations (below) Check out the diagrams. Please run some tests and get back to us.
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Saturday, February 18th, 2017 AT 4:44 PM
Tiny
DYPYZ0
  • MEMBER
  • 2002 CHEVROLET SILVERADO
  • V8
  • 4WD
  • AUTOMATIC
  • 180,000 MILES
My light just came on the dash and the gauge went to around 10 volts. I have battery voltage at the rear of the alternator, but the two wires that plug into the alternator are not hot: running or not. Should either of these two wire be hot.
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Tuesday, June 30th, 2020 AT 2:04 PM (Merged)
Tiny
JAMES W.
  • MEMBER
The two wires in question may or may not be hot, depending on your system. To check your alternator output, do the following.
With the truck at a warm idle, all accessories "off", meter on the 20 or 50 volt DC scale, test accross both posts of the battery. You should get a reading of 12.5 to 14.5 volts. Anything below this, your alternator is bad.
Then, one at a time, with meter still connected, turn your accessories on ie; blower fan, headlights, AC. The meter should not drop below 12.5 volts. Hope this helps.
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Tuesday, June 30th, 2020 AT 2:04 PM (Merged)
Tiny
SUDSMAN1
  • MEMBER
  • 2000 CHEVROLET SILVERADO
  • 5.3L
  • V8
  • 2WD
  • AUTOMATIC
  • 112,000 MILES
In the morning when I first start the truck the voltage output is fine at about 14.2 volts. After I have used the truck for a while, park and turn the engine off, I'll come back and start up again and the voltage shows around 11 volts. It will stay that way for a while until something shifts or wiggles somewhere in the engine, at which point the voltage will then climb up to the normal 14.2 volts. The voltage to the small wire in the plug on top of the alternator reads 1.27 volts (don't know if this is the field wire) while the output is low. Any idea what the voltage should be on the small wire and is that wire fed from the PCM, AND is there a name for that wire.
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Tuesday, June 30th, 2020 AT 2:04 PM (Merged)
Tiny
TY ANDERSON
  • EXPERT
According to my resources there are two small wires. The brown wire is the charge indicator signal. The grey wire is the charge duty cycle controller circuit.
Some alternator will begin to fail with heat, as the alternator warms up parts inside the alternator will expand in side and loose good contact within the circuits and when it cools down the contact improves.
Check the large red cable electrical connections at the alternator and the battery terminal clamps are tight and not corroded. Make sure the belt tension is tight and not really loose. The belt is tensioned automatically by the tensioner pulley so it should be tight enough.
When the vehicle shows it isn't charging, open the hood and tap the alternator with a mallet (do this with the engine running) or the wood handle of the mallet and if this corrects the charging voltage, plan on replacing the alternator assembly
Thanks for the question
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Tuesday, June 30th, 2020 AT 2:04 PM (Merged)
Tiny
SUDSMAN1
  • MEMBER
Hi and thanks for getting back to me quickly. I did as you said (rapped hard on the alternator) and the voltage jumped up to the correct level. I took the alternator apart today and tightened all the screws and cleaned the brushes. There is only one small wire on the plug which now reads 12.6 volts and there does not seem to be a regulator built onto the altenator. Is there a regulator located somewhere else or does the PCM do the regulating? This is one of the towing package alts with higher amperage.
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Tuesday, June 30th, 2020 AT 2:04 PM (Merged)
Tiny
TY ANDERSON
  • EXPERT
The PCM monitors the charging output & controls charging duty.
Good to hear you saved yourself an alternator replacement.
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Tuesday, June 30th, 2020 AT 2:04 PM (Merged)

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