Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum banner
1 - 16 of 16 Posts

·
Registered
Joined
·
8 Posts
Discussion Starter · #1 ·
Hey All,

So I found out that SOMEWHERE in my wiring harness, it's causing my Climate Controls to malfunction and cause a constant .5AMP draw to my battery which is making it so I have to jump start it every single time I drive it.

My thought for the winter is to install a "kill switch" to turn it off so it doesn't cause that draw. I have everything I need, but for the life of me can NOT find the wiring diagram so I can pinpoint the power wire in the harness.

Any help would be greatly appreciated!
 

·
Premium Member
'05 Chevy TB EXT
Joined
·
5,642 Posts
Don't be messing with your computer! No good can .... nor ever has .... come from it.

Fix the problem instead of trying to wire around it.

The "time-to-kill" the battery is important to know. If it's quick ... under a few hours .... there has to be heat radiating from something. Alternators are a prime example of this possibility.

Overnight is hit-n-miss, in that killing a battery needs a heatsink of some kind ... because of the potential in the battery. A .5Amp fuse will never carry enough to dump a battery except perhaps, over a week or so.

You're chasing your tail.
 

·
Registered
Joined
·
8 Posts
Discussion Starter · #3 ·
Don't be messing with your computer! No good can .... nor ever has .... come from it.

Fix the problem instead of trying to wire around it.

The "time-to-kill" the battery is important to know. If it's quick ... under a few hours .... there has to be heat radiating from something. Alternators are a prime example of this possibility.

Overnight is hit-n-miss, in that killing a battery needs a heatsink of some kind ... because of the potential in the battery. A .5Amp fuse will never carry enough to dump a battery except perhaps, over a week or so.

You're chasing your tail.

I've definitely narrowed it down to something to due with the climate controls. When that's disconnected, it won't drain at all. I warranty replaced the controls, since I just bought them last year and installed them.

If the car sits for 8+ hours, the battery is drained. I work 10 hour shifts so I'm jumping it when I go to leave for work then jumping it again when I leave to go home for the day. I know on an older car, I had to wire in a switch for the radiator fan. I'm honestly ready to get rid of it BECAUSE I've been chasing my tail with junk for almost 2 years...
 

·
Premium Member
'05 Chevy TB EXT
Joined
·
5,642 Posts
The word JUNK as a descriptive, makes me want to ignore you from this point .....however, that said .....

On your 1955 Dodge, doing such things as you are want to describe them can be done.

HOWEVER -----> This ain't your 1955 Dodge ... so stop barfing in your own messkit.

It is behoovant upon you to adhere to the idea that you likely won't get away with what you wanna do .... verses what your computerized vehicle will/will not tolerate .... not to mention that repeated discharges are both battery and HVAC Controller KILLERS!!!!!!!

Dependant upon if you now throw a hissy or not ... will grossly affect my wanting to help you any further.
 

·
Premium Member
'05 Chevy TB EXT
Joined
·
5,642 Posts
Look ... this is why people in the business --- and those that are retired --- (that's me) have all the very expensive tools, scanners, diagnostic devices, special gear and equipment ... because we needed it to repair cars and trucks for all the years we were in this business.

Watch this video and see just how complicated it has all become and it keeps getting moreso every day.


My guess is that that cabinet with the big screen and the drawers costs over $30K.


Some of us --- (that's me) continue buying tools and electronic whiz-bangs to keep our hobby alive to us.

Passing out free information is just something we do here --- and I will bend over backwards and bleed real blood for someone who actually CARES and wants to learn.

I wrinkle at people who want a quick fix and won't-can't-don't care about learning anything new or refuse to get their hands dirty or heaven forbid ---> interfere with playing thumb games on their cellphones.

Face it --- we are all owners of cars that are orphans by design and long in the tooth because they are actually old.

BUT --- they require finesse and knowledge that isn't something you get in a cereal box.
 

·
Premium Member
2004 chevy trailblazer_lt
Joined
·
3,229 Posts
APS2002, a 0.500 amp drain on the battery over a 10 hour time period equates to a 5 AmpHour drain on a battery that should have an amp hour capacity of approximately 60 AmpHours assuming you have a Group 78 battery in your TrailBlazer. Since you did not identify Year, Make, Model & Engine, I made the following assumptions as well - 2004 Chevy TrailBlazer, 4.2L I6 engine.

Now, removing 5 AmpHours of power from a 60 AmpHour Group 78 battery leaves 55 AmpHours of power in the battery, which is more than enough to start a 2004 TrailBlazer with the 4.2L engine provided the engine is in good repair.

Now, if you made the 0.5 amp draw rate measurement withing 30 minutes of disconnecting/reconnecting a battery cable, then you are not measuring a parasitic draw. You are actually measuring the current draw from all the various computer modules (ECM, TCM, BCM, etc.) as they refresh their memories. Because of this, you need to come back after at least 30 minutes of setting up the parasitic draw test to see what the actual parasitic draw is AFTER the various modules return to sleep mode.

This makes me think that your problem is in the charging system which includes the battery and the alternator.

Have you had your battery load tested? No, not conductivity tested using a hand held electronic instrument that most auto part stores use to test a battery while it is in the vehicle, but a tester that places at least a 100 - 200 amp load on the battery for a period of time to see how the battery behaves.

Also, have you had your alternator tested to make sure that it is not putting out AC voltage along with DC voltage? A defective alternator will not charge a battery.

Lastly, have you actually put a dedicated battery charger on the battery to make sure the battery has been charged completely?

An alternator will not sufficiently charge a discharged battery unless you are driving several hundred miles at a time.
 

·
Premium Member
'05 Chevy TB EXT
Joined
·
5,642 Posts
....... and more .....................

AC Ripple on any or all of the 3 nodes (see Picture #1 for a NORMAL 3 PHASE ALTERNATOR OUTPUT) of power generation from the alternator will cook a battery that is NOT designed to use AC at all. It cooks the plates and overheats the electrolyte, dropping flakes of the plates to the bottom of the battery where it builds up with the ordinary mulm that collects there ... only much faster until it shorts out the plates by building conductive bridges between the plates ... <sizzle>

#1:
White Rectangle Slope Font Line


So-o-ooo IF the alternator has bad rectifier diodes eg: shorted (see picture #2, B&C )- so that the AC is not removed from the output, it will damage the battery.

Open diode(s), (Picture #2, E) OTOH - are not so much a problem in that the alternator won't will cook the battery, but it keeps the battery from achieving a full charge.

1B:
Rectangle Font Parallel Symmetry Circle




A battery that doesn't get fully charged can freeze the electrolyte (See picture #3) in very cold weather and/or it cannot produce the current to correctly spin the starter under the power needed to rotate the engine - and that helps damage the battery as it tries to start the engine. Low Voltage to the starter will call higher Amperage --- not what the battery LIKES to do, but can if called on to do it --- a few times before it warps the plates from heat.

#3
Font Number Circle Electric blue


Here's the problem: you change the alternator but the battery is already damaged and put unnatural strain on the new alternator and you change the alternator and put it onto a bad battery --- etcetera, etcetera, etcetera. See? I viscous circle.

.... and remember this ----> alternators do NOT LIKE to charge a low battery --- they are designed to replace the power used to start the engine and perhaps to supply bonus power when you have all your accessories ON at idle.
I already told you about the artificial excitement by the ECM to force the alternator to think it's spinning faster than it is by injecting a High Hz signal to the Field during extended idle times when the battery cannot keep up with the load.​
The charging system is very much alive and is constantly under observation by the ECM and as it transitions in and out of idle, it switches from that mode to the other seamlessly.​





.
 

·
Premium Member
2004 chevy trailblazer_lt
Joined
·
3,229 Posts
One other thing to consider, and a battery load test will show it in short order, is if you have a bad cell in the battery. The battery might show a normal voltage when measuring the battery voltage, BUT, under load the battery cannot deliver the required current a starter needs to start an engine.
 
  • Like
Reactions: Ravalli Surfer

·
Premium Member
'05 Chevy TB EXT
Joined
·
5,642 Posts
One other thing to consider, and a battery load test will show it in short order, is if you have a bad cell in the battery. The battery might show a normal voltage when measuring the battery voltage, BUT, under load the battery cannot deliver the required current a starter needs to start an engine.

This is true --- you need a battery brake --- usually a carbon pile with variable resistance to do it best.

I loved my Sun VAT-40.

Gas Machine Electronic device Motor vehicle Metal
 

·
Registered
2008 chevy trailblazer_lt
Joined
·
107 Posts
I was disconnecting my battery multiple times a day, to clear trouble codes related to the thermostat...before I knew it really needed just a thermostat. Anyways, if you can't get it fix or until you get it fixed, I'd put in a quick disconnect or just unscrew a battery cable each time. It might be better to narrow down a fuse that really slows the drain, though. Good luck.

Rob in AZ
 

·
Premium Member
'05 Chevy TB EXT
Joined
·
5,642 Posts
I was disconnecting my battery multiple times a day, to clear trouble codes related to the thermostat...before I knew it really needed just a thermostat. Anyways, if you can't get it fix or until you get it fixed, I'd put in a quick disconnect or just unscrew a battery cable each time. It might be better to narrow down a fuse that really slows the drain, though. Good luck.

Rob in AZ
Why not just pull the ECM fuse for 10 seconds?
 

·
Premium Member
2004 chevy trailblazer_lt
Joined
·
3,229 Posts
RPatton76, I have to strongly disagree with you on this one. Each time the battery is disconnected/reconnected and the internal gears inside the HVAC actuators are stressed, the odds go up significantly that the next time the battery is disconnected/reconnected one or more of the HVAC actuators is going to fail resulting in a significant repair which could include the need to pull the entire dashboard just to gain access to one or more of the actuators.

Using a KAM device essentially eliminates this risk.
 

·
Premium Member
'05 Chevy TB EXT
Joined
·
5,642 Posts
RPatton76, I have to strongly disagree with you on this one. Each time the battery is disconnected/reconnected and the internal gears inside the HVAC actuators are stressed, the odds go up significantly that the next time the battery is disconnected/reconnected one or more of the HVAC actuators is going to fail resulting in a significant repair which could include the need to pull the entire dashboard just to gain access to one or more of the actuators.

Using a KAM device essentially eliminates this risk.
....................so far, he's gotten away with it --- but it will be bitten! Eventually ....
 

·
Registered
2008 chevy trailblazer_lt
Joined
·
107 Posts
> Why not just pull the ECM fuse for 10 seconds? <<
If that will stop his current drain, that might be a quick thing to do.

>Each time the battery is disconnected/reconnected and the internal gears inside the HVAC actuators are stressed, the odds go up significantly that the next time the battery is disconnected/reconnected one or more of the HVAC actuators is going to fail <<
I know for me, I got my 2008 in about 2017 with 128,000 miles on it and several actuators broken. I estimate 3 were broken, but nothing has happened with the 100 other times I disconnected the battery. I have no floor vents, only dash and defrost work. I just haven't ever put in the actuators I have, since there was a 50+ page thread that said "read it all before starting the job" and I've never read all 50+ pages....

Rob in AZ
 

·
Premium Member
'05 Chevy TB EXT
Joined
·
5,642 Posts
If that will stop his current drain, that might be a quick thing to do.


I know for me, I got my 2008 in about 2017 with 128,000 miles on it and several actuators broken. I estimate 3 were broken, but nothing has happened with the 100 other times I disconnected the battery. I have no floor vents, only dash and defrost work. I just haven't ever put in the actuators I have, since there was a 50+ page thread that said "read it all before starting the job" and I've never read all 50+ pages....

Rob in AZ
.. then that is YOUR problem ---- WE write this stuff so people won't destroy their vehicles and yet you still wanna say it's all good?

Crass! How rude! How ignorant!

You do YOU and all the other people here will opt for the logical and intelligent warnings.
 
1 - 16 of 16 Posts
Top