Battery Drain

Tiny
RONALD DEVOLD
  • MEMBER
  • 2002 GMC ENVOY
  • 4.2L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 200,000 MILES
Battery Drains after a few hours of charging. I have replaced the battery twice and tested the alternator.
Tuesday, March 15th, 2022 AT 5:04 AM

1 Reply

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,268 POSTS
Hi,

We need to determine which circuit is causing the battery draw. I don't have a link yet, but here are the directions I wrote for testing for an electrical draw.

Take a look through these and let me know what you find or if you have other questions:

1) Make sure the battery is fully charged.
2) Using a voltmeter or multimeter, confirm the battery voltage is 12v or more.
3) Make sure all electrical components are off, the ignition key is removed, all doors are closed, and anything that could cause an electrical draw.
4) Disconnect the negative battery terminal.
5) Set your meter to DC amp. Start at a higher setting, for example, the 10-amp setting on the meter.
6) With the negative battery terminal disconnected, place the red lead of the meter to the battery cable and the black lead to the negative battery post on the battery.
7) With a setting of 10 amps, you should not get a reading. So, work backward to see when you start getting a reading. The reading should require you to select the milliamp setting.
8) If your reading is above the milliamp setting, you have a significant electrical draw. With the voltmeter still connected, remove one fuse at a time in the under-hood fuse box until you remove one that causes a significant voltage drop on the voltmeter.
9) If none of the fuses in the engine compartment fuse box reduces the draw, then you will need to move to the interior fuse panel and repeat the process. However, it is important to follow step 9 before starting.
10) Disconnect the voltmeter before opening the door otherwise, damage to the voltmeter can occur.
11) With the battery still disconnected, locate the door switch button and place it in the closed position and secure it so the vehicle thinks the door is closed.
12) If there is more than one interior fuse box, you may need to check both.
13) Once you locate the fuse which causes a significant drop in the draw, you have identified the circuit involved. At this point, use the fuse legend in the fuse box to confirm what the specific fuse powers are, and then, using the correct wiring schematic, work through the circuit to locate the problem.

Let me know what you find.

Take care,

Joe
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Tuesday, March 15th, 2022 AT 6:56 PM

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