Question about 2001 Chevrolet Silverado 1500

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Charging system malfunction under load

Under heavy load or when in passing gear, the voltage gauge drops and the headlights dim. This started after I replaced a battery that would no longer hold a charge. The battery, alternator and belt tensioner have all been replaced. When tested at a chevy dealer or parts store this system load test @ 2000 RPM is fine. Also have 12 volts between the ground cable when disconnected and the battery ground terminal.

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If the condition is present for short times only it will not affect anything. It's possible that the crank pulley is glazed and slipping slightly on a hard pull (everything else depends upon that pulley to be properly driven) You can't really duplicate that on a static test. It's also possible that the battery was a bit low when you bought it and needs to have the charge level topped off with an external charger. Otherwise, the only option I can think of offhand would be to obtain an alternator designed for heavy duty service (police version etc) which may be able to deal with the demand.
As your vehicle gets older, resistance in all circuits increases, making little difference during normal operation but can also influence how your vehicle charges. Cleaning / adding additional ground points can help with this.
If it seems that I'm jumping around a bit, I am, but since the charging system is pretty much operational except at that one point, I'm trying to give you some ideas that either in combination, or one alone will be of some help to you.
good luck

Posted on May 25, 2009

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Posted on Jan 02, 2017

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