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1988 Chevrolet S-10 Blazer Utility Base

1988 Chevrolet S-10 Blazer Utility
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June 4, 2012, 11:28 am

Andrew B

Question: What would cause the voltage to drop significantly at 2000 rpms?

A few days ago my check engine light came on in my truck, but all my gauges read appropriately. The light came on with an accompanied electrical sound high pitch sound. The truck runs and drives smoothly with no error except when I hit 2000 rpm's the voltage drops to around 8-9 volts and my battery light comes on. I have had both the battery and alternator tested but both have come back as passed. I believe I have a malfunctioning voltage regulator, but I cannot get my alternator warranted unless it fails.

My vehicle has the 4.3 lt engine.

June 9, 2012, 2:16 am

Tyler O

This does sound like an alternator issue. The voltage regulator is internal to the alternator.

Try retrieving the code from the engine computer if you can.

Most alternator tests can't detect a problem like you are describing.

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