2001 GMC Sierra Battery Drain... No known cause?

[roc2178]

I am at wits end with this issue. I have had this problem with this truck for about 2 years. Here goes it.... Every time the vehicle sits for at least a day, the battery ends up dying, unless I keep it on a charger continuously. I have replaced the battery 4 times within the last 2 years, and have brought it to the dealer and my local mechanic, and have had no luck, as everything checks out OK so both times they have given me a battery service (to clean the battery, connections, etc). I have tried to locate what is actually draining the battery myself, via a test light and pulling each fuse, however this did not help me locate the circuit in which the battery drain was coming from. I thought it was my instrument cluster, as it was not functioning correctly (as it would take anywhere from 20 minutes to 1 hr of driving for it to start working), but I had just replaced the cluster with a new one this week. As for the alternator, I have checked this and it is charging at about 14.3 volts (I also have a spare as I thought it was this). The only other symptom I just noticed was that while the truck is idling, the dash lights, radio and interior lights, seems to "pulsate" with the motor (dim then bright, etc) but the headlights don't seem to do this (well at least noticeably). Please if anyone knows of any direction to point me in I would appreciate it, as I have been driving around with a jumpstarter just to get going for the last 2 years, and it started that the battery would drain after a week of sitting, now it barely hangs on for a day). Then if the battery is totally drained the Passlock system wont let me start it, thus sometimes killing my jumpstarter!! So any info here would also be great. Thanks in advance to anyone that provides any type of insight.

 

[Molson02536]

I am at wits end with this issue. I have had this problem with this truck for about 2 years. Here goes it.... Every time the vehicle sits for at least a day, the battery ends up dying, unless I keep it on a charger continuously. I have replaced the battery 4 times within the last 2 years, and have brought it to the dealer and my local mechanic, and have had no luck, as everything checks out OK so both times they have given me a battery service (to clean the battery, connections, etc).

Try this, disconnect positive battery cable set your multi meter to DC Amperage and connect it inline between the positive battery post and the positive battery cable. see if there is a draw with the key off. If so you have a parasitic draw in the system somewhere. Start removing fuses one at a time until the draw goes away. This will isolate the circuit that has the draw on it, then continue to diagnose inward from there.

Here is also a TSB that may help you, and keep us posted.

#02-06-03-008C: Low Voltage Display on IP Gauge, Lights Dim at Stop Lights, Battery Discharged, No Start, Slow Cranking, Dim Lights at Idle, Low Generator Output - (May 30, 2007)

Subject: Low Voltage Display on IP Gauge, Lights Dim at Stop Lights, Battery Discharged, No Start, Slow Cranking, Dim Lights at Idle, Low Generator Output

Models: 1990-2008 Passenger Cars and Light Duty Trucks (including Saturn)

2003-2008 HUMMER H2, H3

2005-2008 Saab 9-7X

Any vehicle may have a low voltage display (if equipped with gauges), lights that dim at stop lights, slow cranking, no start, low generator output at idle or dim lights at idle when electrical loads are heavy at idle or under slow driving or infrequent usage conditions. These characteristics may be more noticeable with customer added electrical accessories, or with a discharged battery. These are normal operating characteristics of a vehicle electrical system and no repairs should be attempted unless a proven fault has been diagnosed.

During normal driving conditions, when engine speed is above 1000 RPM, the generator is designed to do two things:

• Supply the current necessary to operate the vehicle's originally equipped electrical devices (loads).

• Recharge/ maintain the battery's state of charge.

The following factors may affect generator and battery performance:

• Non-usage of the vehicle for extended periods of time. The vehicle's computers, clocks and the like will cause the battery state of charge to drop (For example; 30 days in a parking lot and the vehicle may not start because of a dead battery or a vehicle which is driven only a short distance once a week may end up with a discharged battery to the point where the vehicle may not start). This would be considered abnormal usage of the vehicle and the normally expected result for the vehicle battery, generator and electrical systems.

• At idle, vehicle electrical loads may exceed the low speed current (amperage) output of the generator and when this happens the shortfall comes from the battery. This will result in a drop in the electrical system voltage as the battery delivers the additional electrical current to meet the demand. This is equivalent to the brown outs experienced by homes and businesses when the electrical demand is more than the supply. See Figure 1.

• Extended periods of engine idling, with high electrical loads, may result in a discharged battery. Attempting to recharge a battery by letting the engine run at idle may not be beneficial unless all electrical loads are turned "OFF".

• Increased internal generator temperatures from extended idling can also contribute to lower electrical system voltage. As the generator's internal temperature rises, the generator's output capability is reduced due to increased electrical resistance.

The following are some typical examples of electrical loads:

System
Amperage Load

Rear Window defogger
25

Electric AIR Pump
25

Heated Seats
5 Amps per seat

Headlamps (high)
20

Blower Motor (High)
20

Headlamps (low)
15

Brake Lights
6

Windshield Wipers
6

Ignition
6

Depending on the vehicle application, generator current (amperage) output at engine idle speeds of 600-700 RPM can be as low as 35 percent of the full rated output. With enough electrical loads "ON", it is easy to exceed the generator current (amperage) output when the engine is at an idle of 600-700 RPM. This is a normal condition. The battery supplements for short periods of time. Items that affect the vehicle's electrical system current and voltage at idle are the number of electrical loads being used, including add-on accessories, and extended idle times. When the vehicle speed is above approximately 24 km/h (15 mph), the engine/generator RPM is high enough and the generator current (amperage ) output is sufficient to supply the current (amperage) requirements of the vehicle as originally equipped and recharge the battery.

Dimming lights at idle may be considered normal for two reasons:

As the engine/generator speed changes, so will the current (amperage) output of the generator. As a vehicle slows, engine/generator RPM slows, and the current (amperage) output of the generator may not be sufficient to supply the loads, the vehicle system voltage will drop and the lights will dim. Dimming of the lights is an indication that current is being pulled from the battery. If the battery is in a low state-of-charge (discharged condition), the driver will notice a more pronounced dimming than a vehicle with a fully charged battery.

When high current loads (blower, rear defogger, headlamps, cooling fan, heated seats, power seats, electric "AIR" pump, or power windows) are operating or cycled "ON", the generator's voltage regulator can delay the rise in output. This effect, usually at lower engine speeds, can take up to ten seconds to ramp up the generator output. This is done to avoid loading the engine severely. To increase current (amperage) output, additional torque is consumed by the generator. The engine computer (PCM) will ramp up engine/generator speed in small steps so engine speed variations are not noticeable to the driver.

For diagnosis of the battery and or the generator, refer to the appropriate Service Information or Corporate Bulletin Number 05-06-03-002B.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

© 2008 General Motors Corporation. All rights reserved.

 

[roc2178]

Thanks Molson! I just finished going through both fuse boxes and with no luck. The draw is .015 amps and I cannot find what is drawing this power. I Do have a plow connected and a remote starter, however I disconnected both of these and have had absolutely no luck as the meter still read .015 amps. I don't know what else to do! Thanks for your suggestions.

 

[roc2178]

Thanks Molson!! I seem to have no luck! I have tried to go through the fuses and with no luck. I went through the engine compartment box and the one inside the cab, I just cannot seem to locate the draw! It is drawing .015 AMPS and everytime I pull a fuse it doesnt go away. I have no idea what else to do.

 

[Pale_Rider66]

find the fix yet?

Hey there,,,,,,,,,,,,,not sure if you found the problem yet but after reading your post.........it sounded exactly like the problem i had a few years ago with a Z34 Lumina. The starter was shorting out and killing the battery.............the windings in the starter would get hot from the exhaust pipe.............and eventually drain the battery.............replaced the starter and "vloila" problem fixed............

 

[happy 2011]

well this will not fix your tk but will fix your dead battery problem. Just install a battery shut off switch in the cab of the tk. So when you shut off your tk for the day you can just filp a switch and shut off the battery power to the tk as well. Total cost is about 100 bucks for switch and cables.
Not sure you want to do this but just a idea for ya.

Good luck