Battery drain GM vehicles

acesover · By: **acesover** On: Mon Sep 14, 2009 3:55 pm

I have a 08 GMC Canyon, it's been back to the dealer three times for the battery going dead. If it's not started within 48 hrs the battery goes dead. The last time I had it back they told me I had a bad battery and installed a new one. (last month) I returned home yesterday after being away for a week, Guess what! DEAD as a door nail.
Anyone else ever hear of battery drain on GM vehicles, I think it's the Onstar.
Ray

009to090 · By: **009to090** On: Mon Sep 14, 2009 3:59 pm

Pull the fuse for Onstar, and see if it still goes dead.
Also, test each fuse circuit to see which is drawing current.

Poconoeagle · By: **Poconoeagle** On: Mon Sep 14, 2009 5:46 pm

The average auto battery is around 65 amp/hr. meaning a 1 amp draw could therotically exist for 65 hrs.... I dont believe the onstar is the issue. I would bet if there were any aftermarket electronics added or any "dealer installed" devices, i.e. trailer brakes? towing package ect. , the problem can always be traced back to there.

If you disconected the negative battery cable, after closing any hood switch or door switch and allowing any light timers to cycle... and connected a regular old 12 test light between the negative cable and the negative post on the battery it will light if there is any draw. now a incadensent bulb is best as you can determine a faint glow vs a bright light. the memory supply to radios and computers will have a slight draw and usually you can see the difference between a "headlight on" draw and a mili-amp draw.

as this draw lights up the test light bulb, pull one fuse at a time till the light goes out. many fused circuts are only hot when the key is energized. Now I also have seen and sometimes start diagonoisis by disconnecting the alternator feild wire's as a defective built in regulator can draw.

the cigar lighter / power recepticle are un switched.

it takes much patience to find but can be done. any new electronics ?? gps ? those factory fog lites???

acesover · By: **acesover** On: Mon Sep 14, 2009 8:03 pm

Thanks guys
Everything is factory install, no new electronics or anything else. I just got a letter from my dealer, GM has taken away his dealership after 53 years. They are sending all customer service to a Cadillac dealer just down the road. I'll let them take one more look.
Thanks
Ray

Poconoeagle · By: **Poconoeagle** On: Mon Sep 14, 2009 8:05 pm

Good Idea Ray. make sure you tell them that the old dealer couldnt find the problem after 3 attempts

the caddy boys have been dealing with freaky electrical ghosts for years.....

009to090 · By: **009to090** On: Mon Sep 14, 2009 8:06 pm

Long shot...... Does that thing have a cargo lite in the the back???? Check to make sure it wasn't left on? :idea:

Poconoeagle · By: **Poconoeagle** On: Mon Sep 14, 2009 8:15 pm

Hmmm I just traced down a interior lite/cargo lite staying on 30 min or more and the problem was a funky switch, located on the door latch mechinisim inside the door. instead of a button switch in the jam the designers incorporated it into the lock/latch! That was brought to us by the "Built ford tough" guys.... former fiat engineers........

samhill · By: **samhill** On: Tue Sep 15, 2009 8:25 am

It`s under warranty I wouldn`t do anything to it but take it back to get it fixed or turn it back in under the lemon law.

acesover · By: **acesover** On: Tue Sep 15, 2009 8:49 am

The dome and cargo light have a override switch to keep them off and I use it, I don't even use the raido any more. I really like the truck... but lemon law, it's got me thinking.
thanks guys
Ray

Sting · By: **Sting** On: Tue Sep 15, 2009 11:04 am

Parasitic voltage drains on vehicles can be frustrating. The dealer tech - most likely on flat rate - Is not being paid to diagnose -- just change parts - so your not getting the vehicle fixed.

You can do it your self - as outlined above - disconnect the negative cable and place a volt meter in line with the cable and battery. Voltage should read less than .08volts closer to .05 volts the better but the ECM the radio the charging system all need voltage to hold memory.

First thing to disconnect is the alternator -- and read the volt meter again. Did it change -- is that the problem?

no -now work your way back - disconnect or unplug anything easy and check again - pull all the fuses -- one at a time and read the volt meter each time

finally, disconnect the large body plug at the fire wall - there, now you isolated the system into two pcs -- front and back -- read the meter again -- did it change? if no the problem is still connected -- if yes -- the problem is further down the line - tear the dash out and keep probing/looking.

I rebuilt a fire damaged Gm in a previous life and months later it came back with the same trouble -- turned out a condenser to dull static in the radio had gone closed and was drawing 12 volts all the time -- very low amps - but it was just like leaving the dome light on all the time --

djackman · By: **djackman** On: Wed Sep 16, 2009 2:04 am

If troubleshooting with a test light note that some modules may stay powered up for a few minutes after shutdown. Test light method on late model cars with light control (et al) modules can be sketchy - if the test light can't flow enough current to turn things "on" the modules may never start enough to turn off. Jump over the testlight with a cliplead for a few minutes to get everything settled down, then remove the jumper.

An amp meter is really the way to go, a 5 amp meter that has a descent scale under 1A will do.

I troubleshoot a lot of late model Fords, usual rule on those is under 50ma (.05 Amp) in a true "off" state. '08 Ford CVPI will hang at 150ma for about 20 seconds after the dome light goes off, then drop to ~100ma, then finally 30-50ma.

In the realm of oddball draws - trailer connector with water intrusion, alternator drawing while off, randomly sticking relays, bad radio.

I checked '07 Alldata (don't have 08) and no TSB's for your problem.

- Bob

mwcougar · By: **mwcougar** On: Wed Sep 16, 2009 8:42 am

hey congrats

you have on of GM FREE FEATURES

we have had 2 chevy 3/4 trucks that have done that also

dealer never found a reason why..... had to shut of the dome cargo light off.....hmmm ya think
after 9 years they wound have fixed that one..... not GM hmmmm never seen fords do that
but hey goes with the prox switch on the antitheft system on grand ams...read up on that
if you like GM electronics. why are americans buying jap cars.....hmmmm just sad.
on the flip though i drive old blue at work.. a 1992 chevy pick-up..... we keep fixing her
up and try to preserve her... only lost a engine on that one....
on the new big white she lost a battery also within a month.... i think that was a dome
light too.... in general we make good trucks.. the problem is in the details... that piss people
off.... dome lights that dont shut off, antilock brake systems that fail in 30,000 miles because of water
turn signal systems fail, eats rotors and brakes in 15000 miles..... fords.... window openers,ball joints,pcm relays
nothing worse than your deisel not starting, calipers. dodges.. that brake calipers.... again.

owner of or work on

2001 grand am 70,000
1999 ford f250 deisel 70;000
1993 subaru 120,000
1969 mustang 125000
1969 cougar 125000
1992 checy 3/4
2001 chevy 3/4
2006 chevy 3/4

have fun all

acesover · By: **acesover** On: Sat Sep 26, 2009 12:04 pm

After four days at the dealer they found the problem, the brain on the OnStar didn't shut it off, so they tell me.
Ray

Poconoeagle · By: **Poconoeagle** On: Sat Sep 26, 2009 12:53 pm

well cool. guess several days after you get it back will tell.

sometimes a dealer management team will tell the customer the warrentee fault was exactly what the customer suggested to instill peace of mind and faith. really only the tech that found it knows.
the tech sometimes misleads the manager who inturn passes the buck back to the manufacturer so as to justify a warrentee claim and thus is how modern politics rolls down hill.

bottom line really is.... is it fixed? if so then life can move foward!! congrats 8-)

acesover · By: **acesover** On: Sat Sep 26, 2009 5:04 pm

When I droped if off I didn't tell them what I thought was wrong with it, they came to that conclusion. They seemed to be rather certain that was the problem, I'm sure the new module for the Onstar wasn't cheep. Time will tell.

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