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73-87 Chevy _ GMC Trucks => Electrical => Topic started by: MaxmillianS on March 23, 2015, 04:59:16 pm

Title: Volt meter moves when blinker is on
Post by: MaxmillianS on March 23, 2015, 04:59:16 pm: Like the title says when I have my blinkers on the volt meter moves about a cm every time they blink, think its just a bad ground?
Title: Re: Volt meter moves when blinker is on
Post by: Irish_Alley on March 23, 2015, 06:34:14 pm: its normal as far as i know. think of it like this you alt doesnt just produce 14 volts all the time, it produces whats needed i.e. 14.1 volts just running vs 14.1 volts with the headlights on. it puts out 14.1 volts depending on the draw and it takes a split second for the alternator to sense how much draw your putting on it. so when the volt needle moves its because of that slight delay
Title: Re: Volt meter moves when blinker is on
Post by: enaberif on March 23, 2015, 07:48:05 pm: Blinkers shouldn't make a volt meter move at all. Technically the only time you should see a volt meter change is under extreme heavy draw like power windows.
Title: Re: Volt meter moves when blinker is on
Post by: blazer74 on March 23, 2015, 09:11:01 pm: Possible diode in the alternator

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Title: Re: Volt meter moves when blinker is on
Post by: MaxmillianS on March 24, 2015, 12:52:54 pm: Alternator is brand new as of a month ago
Title: Re: Volt meter moves when blinker is on
Post by: blazer74 on March 25, 2015, 05:28:19 am: Was it doing this prior to the alt change?

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Title: Re: Volt meter moves when blinker is on
Post by: Irish_Alley on March 25, 2015, 06:00:37 am: put a volt meter on the battery and see if it really does drop. could be a bad ground, but i know most if not all of my trucks do this
Title: Re: Volt meter moves when blinker is on
Post by: enaberif on March 25, 2015, 11:52:52 am: Quote from: Irish_Alley on March 25, 2015, 06:00:37 am
put a volt meter on the battery and see if it really does drop. could be a bad ground, but i know most if not all of my trucks do this

LOL then you got a problem somewhere. This is not normal behavior.
Title: Re: Volt meter moves when blinker is on
Post by: Irish_Alley on March 25, 2015, 03:33:57 pm: oh i have a lot of problems lol
Title: Re: Volt meter moves when blinker is on
Post by: Shifty on March 26, 2015, 12:29:21 pm: My 87 V30 and 87 Z/28 both do this....it may not be normal, but the Z/28 has had the same alternator for about 50k, battery 4+ years.
Title: Re: Volt meter moves when blinker is on
Post by: frotosride on March 26, 2015, 06:02:47 pm: Because of the wiring design there are often voltage drops in the cab. Like Irish-Alley said the alternator puts out varying voltage. If you have a three wire alternator then the small red wire that goes directly to the positive output lug is the voltage sensing wire. If you relocate this wire to the cab end of the wiring harness you will notice a drastic increase in electrical performance. The sensing wire works OK in the factory location but with most major loads under the hood being so close to the battery it. Cannot sense a large drop inside the cab.