[acenface21]

I've got a 2005 GMC Envoy XL. It use to be that if it wasn't driven for a week the battery would die. Now the battery dies in less than 24 hours after being driven.

It does have an aftermarket head unit as well as an overhead DVD player, both installed by a 3rd party, through the dealer when it was purchased...so I don't know if the problem existed before.

Regardless, I've taken it to the dealer and they can't find any problems. I've taken it to an independant electrical shop and had it diagnosed. They can't find any drains or any other problems with it. I'm on the second new battery and it's just getting ridiculous.

Any known issues of this type? I can't find anything online...please help!

 

[the roadie]

Classic parasitic drain. Sometimes the Onstar module won't go to sleep. It could be any of 15-20 modules.

How clever was the independent shop, and what level of drain did they detect and declare not to be a problem? Did they know they had to measure current coming out of the battery WITHOUT ever disturbing voltage going to the vehicle so the modules wouldn't reset themselves?

Did they keep it overnight to catch it in the act?

On our platform, you can't just yank the wire off the battery and insert a milliammeter in series with the wire you just pulled off. The temporary disconnection messes up the state of the vehicle and none of the tests are valid.

 

[sBoddie]

Rear liftgate

We had a similar issue for quite a while. Check the rear liftgate (not the window). Pull the handle to open it... listen for the power release to click. Then shut the tailgate... listen for it to engage. THEN remote/keyfob lock.

Sometimes it gets stuck in the partial unlocked position and keeps cycling all night. We've gotten in the habbit of listening everytime somebody opens it. Happens most often when you close it then remember something else and open it again (like unloading luggage/groceries).

srb

 

[laini30]

We have had almost the exact same scenario with our 2006 trailblazer. There for awhile, it would go dead after about a week of not being driven, which it had never done that before (had it for 3 years before). We changed the battery, we have taken it down to have the draw checked and everything was within normal range. They suggested that we buy a solar charger. Now, when it won't start, all the lights come on and when you turn the ignition key, it doesn't even click when you try to start it like it normally does when the battery is dead. All my husband did was touch the jumper cables to it and it started up immediately. We have been to a GM dealer and they have no idea what is going on because they can't find anything wrong. Now, it goes dead every day, and it's even worse with the cold weather at night. The one thing I have noticed and I have no idea if it is related, but the oil sensor went out and the foot pedal motor quit working about the same time this started to happen and there is a clicking noise in the back she we turn on the rear heat/ac...it sounds like something is flapping inside and it doesn't blow air for awhile. Someone told us that it might need a new computer module, but I really don't have a clue about this stuff.

 

[Don the Non]

We have had almost the exact same scenario with our 2006 trailblazer. There for awhile, it would go dead after about a week of not being driven, which it had never done that before (had it for 3 years before). We changed the battery, we have taken it down to have the draw checked and everything was within normal range. They suggested that we buy a solar charger. Now, when it won't start, all the lights come on and when you turn the ignition key, it doesn't even click when you try to start it like it normally does when the battery is dead. All my husband did was touch the jumper cables to it and it started up immediately. We have been to a GM dealer and they have no idea what is going on because they can't find anything wrong. Now, it goes dead every day, and it's even worse with the cold weather at night. The one thing I have noticed and I have no idea if it is related, but the oil sensor went out and the foot pedal motor quit working about the same time this started to happen and there is a clicking noise in the back she we turn on the rear heat/ac...it sounds like something is flapping inside and it doesn't blow air for awhile. Someone told us that it might need a new computer module, but I really don't have a clue about this stuff.
[There is a module called a blend door actuator located in the right rear. When it fails the gears inside, it keeps spinning and clicking till it runs the battery down. Search part 604-111. Like $20.

 

[Ravalli Surfer]

Batteries hold a tremendous amount of potential energy - stored in the electrolyte. If something's taking your battery down that fast - it has to heat up... or at least get fairly warm.

If I had this problem, I'd get it jump started - idle for about 15 minutes* and then go for a 5 or 6 mile ride.

• (* this is because alternators do NOT like to charge a very low or dead battery and letting it idle a while will keep the poor thing from killing itself trying to catch up)

Park the vehicle and after an hour or so - go to it and physically touch and feel everything under the hood - emphasis on the alternator since it is capable of eating a battery and it will get pretty hot.

I don't suspect lights or radios or stereos, etc.

• Motors might be capable of doing it - but they would be running and at least making noise.
• Window motors? Maybe - listen for them - turn the key on a test them.
• 6-way power seat motors? Nah! They'd be noisey and make a lit of smoke.
• The starter would smoke with the size and capacity for the large windings to carry current - it would be a short life and I'm sure it would not start the vehicle when you jumped it anyway.... good or bad battery.. so I don't suspect it as the bad player here.

As high of a draw that is required to take a battery to it's knees - it HAS to radiate heat.

My money's on the alternator - but let me know what you find anyway - I can take being wrong --- again.