Parasitic draw

625 Views 7 Replies 3 Participants Last post by Kking79, Mar 17, 2020

Kking79

Discussion Starter · Mar 17, 2020

2003 Silverado has a draw that is .75 amps to the alternator from the battery when everything is turned off. If I unplug the alternator from the harness the draw stops and it drops to zero. I also have a battery indicated on the cluster that stays on, as well as the PRNDL. Not sure if they are related but both still happen when the other is unplugged. What will cause this and should my next step be sending the cluster in for repair? Also I have already reflowed the solder on the cluster resisters.

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de-nagorg

· #2 · Mar 17, 2020

The alternator needs that draw to generate a charge to keep everything running and recharge the battery.

There should be a relay in the circuit that shuts off the draw, when it is not needed.

May be internal to the alternator, and testing the alternator will show the defect.

ED

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de-nagorg

· #5 · Mar 17, 2020

Kking79 said:
Why would the alternator need this power draw with the engine and truck off? Should it not be a key on hot? The alternator is brand new from manufacturer not a rebuild also with less than 2 hours of run time

It don't need it when not running.

The relay is either in-line from the battery to the alternator + terminal, or internal, and disassembly is needed, which will VOID the warranty.

ED

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