Information on Intermittent Battery Drain Diagnostic Tips and Recommendations

An intermittent battery drain may be difficult to duplicate, and may only occur when certain conditions are met. Generally, an intermittent is caused by faulty electrical connections and wiring, malfunctioning components or aftermarket equipment. The purpose of this bulletin is to provide the technician with the following diagnostic tips and/or recommendations that may prove to be beneficial in locating and repairing the condition.

Normally a draw, which takes the battery level down overnight after operating the vehicle the day before, is rather large and may be related to a switch, relay or other electric/mechanical device.

A small battery draw, which takes several days to take the battery to a low state of charge or below the level required to start the engine, may be a bulb or module staying on.

Check for diagnostic trouble codes (DTCs) and question the customer regarding the battery drain.

1. How long does it take for the battery to discharge? This will help determine if the draw is large or small.

•	Were any lights or accessories left on overnight?

-	video displays

-	phone chargers

-	radar detectors

-	map or dome lights

-	headlights

•	Does the customer leave the key in the ignition? Modules may be staying active or powered up.

•

Ask the customer if they use the accessories (Radio, DVD player, etc.) with the key in the ON position but with the engine off. This may contribute to draining the battery, which could result in a low battery state of charge and difficulty cranking the engine. If the customer uses their accessories with the engine off, ask them to turn the key to the ACC position instead of the ON position.

Important: Ask the customer to provide the accessory and/or power cord to aid in the diagnosis of the condition, if necessary.

2. Is the vehicle equipped with any non-original equipment including cell phone, remote starter, extra lighting, satellite radio, DVD player, amplifiers, subwoofers, additional speakers, alarm systems, snowplow, trailer brakes, cruise control, 12-volt vehicle heater or etc.
3. What are the customers driving habits or primary use of the vehicle?

•	Is the vehicle parked for extended periods of time?

•	Is the vehicle used primarily on vacations or just weekends?

•	Is the vehicle used to tow a trailer and/or camper?

•	Is the vehicle used for snow plowing or contractor use?

•	Inspect the vehicle to determine if additional wiring harnesses were added to the vehicle and left on the vehicle after the accessory was removed. Some of these additional items may include:

-	trailer harness

-	trailer brake control module

-	aftermarket audio equipment

-	i-pod and/or MP3 adapters

-	video game system

-	GPS or navigation system

-	additional lighting

-	two-way radio and/or "CB"

-	fog lamps and/or off road lights

-

winch

-	snow plow and/or controls

-	salt spreads

4. What is the previous history on this vehicle?

•	Has this vehicle ever been in an accident?

•	Were any repairs performed on this vehicle?

•	Were any parts replaced?

If a vehicle will start and then not start in a very short period of time, this condition may be created by a loose or corroded connection. In most situations a battery in a good state of charge cannot be drained within minutes unless a short condition or heavy load is placed on the electrical system. The following items are also possible areas of starting or charging system concerns and should be considered as a part of your diagnosis. For more information refer to the Symptoms -- Engine Electrical diagnostic procedure in SI.

1. Verify the battery cable connections. It is possible for the negative and/or positive terminal connector nut to tighten without making a good electrical connection on the battery terminal. The top of the negative battery post should be slightly above the top of the cable clamp. Refer to Corporate Bulletin 07-06-03-002B on "Inspecting Top Post Battery Cable Bolts".
2. Verify the battery condition and state of charge using the Midtronics tester and a VAT40 or equivalent tester. Refer to the following diagnostic procedures and/or bulletins in SI for additional information.

•	Battery Common Causes of Malfunction in SI.

•	Battery Inspection/Test in SI.

•	Battery Charging in SI. Refer to Corporate Bulletin 02-06-03-009C on "Battery Charging Tips".

3. Verify proper operation of the charging system. Refer to the Charging System Test procedure in SI and additional bulletin information.

•	Refer to Corporate Bulletin 02-06-03-008D on "Low Voltage Display".

•	Refer to Corporate Bulletin 07-06-03-009A on "Information on Voltmeter Gauge Fluctuation".

Important: Install the Parasitic Load Tool and then road test vehicle for 30-40 minutes, activate all accessories. Open and close all doors, windows, seat switches, map light switches, etc. Visually inspect cigarette lighters and inside power sockets for debris. Sometimes coins may fall into the power socket and cause a short condition.

4. Verify that the vehicle does not have a parasitic battery drain. Refer to the Battery Electrical Drain/Parasitic Load Test procedure in SI.

•	If a draw is found, determine the cause by touching and/or removing fuses, relays, and connectors to the suspect components. Refer to Wiring Systems and Power Management in SI.

•

The digital OnStar® system will remain in DIGITAL STANDBY for the full 48 hours after the last ignition cycle. Normally a technician may see a drain that is reading approximately 20mA to 70mA with occasional spikes that may vary around 175mA. The OnStar® module is capable of receiving incoming calls and readings may jump to 250mA or more during the call.

5. Verify that the front and/or rear Heating, Ventilation and Air Conditioning (HVAC) blower motor turns off with the key in the OFF position. If the blower motor stays on, refer to the Blower Motor Always On diagnostic procedure in SI. Some vehicles may be equipped with an after blow module. Refer to Afterblow Enabling in SI.
6. If the vehicle is equipped with aftermarket accessories, verify that they are not a source of concern. Such as aftermarket radios, DVD players, i-pods, amplifiers, cell phone charges, etc. Remove or disable if necessary and retest the vehicle. Refer to the Checking Aftermarket Accessories procedure in SI.
7. Verify that there are no loose connections at the 175 amp mega fuse and/or fuse block. Refer to Corporate Bulletin 08-06-03-007 on "Intermittent Electrical Operations".

Important: Vehicles equipped with the GM Navigation Radio may access the map data after the key is removed from the ignition and the door is open up to three minutes.

8. Verify that the Retained Accessory Power (RAP) system is operating properly. For more information, refer to the Retained Accessory Power (RAP) Malfunction procedure in SI.
9. Verify that there are no relays or components under the hood that are ON or running when the engine is OFF, such as electric cooling fan motors or other electrical components.
10. Refer to the following information and bulletin on additional areas of concern.

•	A fuel pump relay sticking concern. Refer to Corporate Bulletin 06-06-03-011B on "Hum or Buzz Noise from Rear of Vehicle". This bulletin applies to vehicles built prior to October 13, 2006.

•	A rear door lock relay sticking concern.

-	If you experience this concern, check the rear door lock relay for a sticking condition.

-	If the relay is stuck in the lock position, replace the left IP fuse box. The rear power door lock relay is internal to the left IP fuse block and can't be replaced separately.

Caution: Circuit 1240 (Left Doors) and Circuit 1340 (Right Doors) are protected by 25 amp circuit breakers that may be hot to the touch, if the circuit is shorted to ground.

11. Check circuit 1240 (Red/White) wire for a short to ground (located on the driver's side) or circuit 1340 (Red/White) wire (located on the passenger's side) "B' pillar area near the seat belt retractor.
12. Inspect the driver and/or passenger door module harness for pinched or damaged wires.

If the above information did not help fix the condition, refer to normal SI diagnostics for further diagnosis and repair.

Technicians should show actual repair order clock time (clock on/clock off) when diagnosing and repairing the vehicle. All time should be claimed against the appropriate Labor Operation based on the repair that corrected the condition.