Anyone have electrical knowledge about SN95?

Chris98vobra said:

I've got a bit more data. Was able to steal some time this morning to do some electrical tests. I checked current draw from my battery and removed 4 different fuses, numbers #1, #4, #7, #10. Pulling #1 and separately pulling #10 dropped the draw from 1.1A to .97A each. I didn't try testing with both removed at the same time. The other two made little differences. But when I checked those two fuse connections with the fuse out and ignition off, I found voltage where there should be none. In 3 cases 12v but with fuse #7 (ABS) I only saw 7.5v. I then turned on the ignition but the voltage stayed at 7.5v at #7. Seems like there is a connection, though poor, to #7. That probably explains my ABS light. There are many other fuses I could have pulled and tested and I suspect there may be others showing voltage too. Does anyone know if all of the fuses under the dash are switched by the ignition switch module? If all of these come through the Ignition Switch Module, doesn't this indicate a module problem?

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1. If equipped, disable the approach detection feature.

1. Make sure the fuse box(es) are accessible without turning on the interior lights or the underhood lights.

1. Drive the vehicle for at least 5 minutes over 48 km/h (30 mph) to activate the vehicle systems.

1. NOTE: If equipped with an automatic transmission and the vehicle has an IPC PRNDL indicator, verify the gear selector lever is in the park position and is operating correctly. A fault in the park position indicator circuit can prevent modules from transitioning to sleep mode.

1. Connect a fused jumper wire (30A) between the negative battery cable and the negative battery post to prevent modules from resetting.

1. Disconnect the negative battery cable from the negative battery post without breaking the connection of the fused jumper wire.

1. NOTE: It is important that continuity is not broken between the battery and the negative battery cable when connecting the meter. If this happens, repeat the time out/power down procedure.

1. NOTE: If the meter settings need to be switched or the test leads need to be moved to another outlet, reinstall the fused jumper wire to avoid breaking continuity.

1. If equipped with auxiliary battery(s), ensure that the auxiliary battery(s) are disconnected when measuring current draw at the primary battery, to ensure the meter or inductive amp probe measures all current draws present. Disconnect the auxiliary battery(s).
   Refer to: Battery Disconnect and Connect (414-01) .

1. Note the amperage draw. Draw varies from vehicle to vehicle depending on the equipment package. Compare to a similar vehicle for reference.

1. NOTE: If the vehicle sits for an extended period of time and the battery drains, there is the possibility of a control module staying alive and not going into sleep mode. If a control module stays alive, it can result in battery drain. If a control module is suspected, isolate individual modules by disconnecting them one at a time and note if the excessive draw goes away.

1. When the current level drops to an acceptable level after removing a fuse, the circuit containing the excessive draw has been located. Reinstall the fuse and allow the vehicle to sit with the key out of the ignition for at least 75 minutes (depending on region) to allow the modules to time out/power down again.

1. The excessive draw can be isolated by continuing to pull subsystem fuses and disconnecting components. Do not reinstall the fuses or connect components until testing is finished. To correctly isolate each of the circuits, all of the fuses may need to be removed, then install one fuse and note the amperage draw, remove the fuse and install the next fuse. Continue this process with each fuse.

1. If excessive current draw is isolated to a specific module, verify if a module input is the cause of the concern. Refer to the corresponding workshop manual system operation and component description section to determine the inputs (hardwired or network messages) received by the module in question.

1. Check the Wiring Diagrams manual for any circuits that run from the battery without passing through the main fuse box or other fuse box(es). If the current draw is still excessive, disconnect these circuits until the draw is found. Disconnect the generator(s) electrical connections and retest if the draw cannot be located. The generator(s) may be internally shorted, causing the current drain.

Vinnie_B said:

Did you properly put the car into sleep mode before testing?

Parasitic Battery Drain test​

Check

NOTE: No factory-equipped vehicle should have more than a 25 mA (0.025 amp) – 50 mA (0.050) draw depending on the vehicle's accessories. Check for current drains on the battery in excess of 25 mA (0.025 amp) – 50 mA (0.050) with all the electrical accessories off and the vehicle at rest for at least 75 minutes (depending on region). Current drains can be tested with the following procedure.

NOTE: Many electronic modules draw 10 mA (0.010 amp) or more continuously.

NOTE: Typically, a drain of approximately 1 amp is attributed to an engine compartment lamp, glove compartment lamp or interior lamp staying on continually. Other component failures or wiring shorts are located by selectively pulling fuses to pinpoint the location of the current drain. When the current drain is found, the meter reading falls to an acceptable level.

NOTE: To accurately test the drain on a battery, use an in-line ammeter between the negative battery post and its respective cable. Use of a test lamp or voltmeter is not an accurate method.

1. If equipped, disable the approach detection feature.
2. Make sure the fuse box(es) are accessible without turning on the interior lights or the underhood lights.
3. Drive the vehicle for at least 5 minutes over 48 km/h (30 mph) to activate the vehicle systems.
4. NOTE: If equipped with an automatic transmission and the vehicle has an IPC PRNDL indicator, verify the gear selector lever is in the park position and is operating correctly. A fault in the park position indicator circuit can prevent modules from transitioning to sleep mode.

Allow the vehicle to sit with the ignition off for at least 75 minutes (depending on region) to allow the modules to time out/power down.

1. Connect a fused jumper wire (30A) between the negative battery cable and the negative battery post to prevent modules from resetting.
2. Disconnect the negative battery cable from the negative battery post without breaking the connection of the fused jumper wire.
3. NOTE: It is important that continuity is not broken between the battery and the negative battery cable when connecting the meter. If this happens, repeat the time out/power down procedure.

NOTE: The meter must be capable of reading milliamps and should have a 10 amp capability.

Connect a meter between the negative battery cable terminal and the negative battery post.

1. NOTE: If the meter settings need to be switched or the test leads need to be moved to another outlet, reinstall the fused jumper wire to avoid breaking continuity.

Remove the fused jumper wire.

1. If equipped with auxiliary battery(s), ensure that the auxiliary battery(s) are disconnected when measuring current draw at the primary battery, to ensure the meter or inductive amp probe measures all current draws present. Disconnect the auxiliary battery(s).
   Refer to: Battery Disconnect and Connect (414-01) .
2. Note the amperage draw. Draw varies from vehicle to vehicle depending on the equipment package. Compare to a similar vehicle for reference.
3. NOTE: If the vehicle sits for an extended period of time and the battery drains, there is the possibility of a control module staying alive and not going into sleep mode. If a control module stays alive, it can result in battery drain. If a control module is suspected, isolate individual modules by disconnecting them one at a time and note if the excessive draw goes away.

NOTE: For vehicles equipped with aftermarket equipment containing electrical connections, disconnect the aftermarket to factory connections to isolate the body from the chassis.

NOTE: Vehicles may be equipped with multiple fuse box locations.

If the current draw is excessive, remove the fuses from the main fuse box one at a time and note the current drop.

1. When the current level drops to an acceptable level after removing a fuse, the circuit containing the excessive draw has been located. Reinstall the fuse and allow the vehicle to sit with the key out of the ignition for at least 75 minutes (depending on region) to allow the modules to time out/power down again.
2. The excessive draw can be isolated by continuing to pull subsystem fuses and disconnecting components. Do not reinstall the fuses or connect components until testing is finished. To correctly isolate each of the circuits, all of the fuses may need to be removed, then install one fuse and note the amperage draw, remove the fuse and install the next fuse. Continue this process with each fuse.
3. If excessive current draw is isolated to a specific module, verify if a module input is the cause of the concern. Refer to the corresponding workshop manual system operation and component description section to determine the inputs (hardwired or network messages) received by the module in question.
4. Check the Wiring Diagrams manual for any circuits that run from the battery without passing through the main fuse box or other fuse box(es). If the current draw is still excessive, disconnect these circuits until the draw is found. Disconnect the generator(s) electrical connections and retest if the draw cannot be located. The generator(s) may be internally shorted, causing the current drain.

If equipped with window one-touch up, perform the window motor initialization after the negative battery cable terminal is connected to the negative battery post.

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Chris98vobra said:

Thanks for all of this. Yes and no about the sleep test. I saw and read that write up about doing the parasitic drain test. When I first tested the current draw I allowed the car to sit for over an hour and the drain stayed the same at 1.1 amps. I suspect that the amount of drain is so large or the reduction due to sleep mode so small that I didn’t notice the reduction. The other possibility is that the active draw circuits are keeping the car from going into sleep mode. Either way, there absolutely shouldn’t be voltage wheee I am measuring it in the fuse box while the key is off.

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