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Gary, ASE Certified Technician
Category: GMC
Satisfied Customers: 16742
Experience:  GCM master tech over 25 years
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My h3 is not keeping charge. had a parasitic drain test

Customer Question

my h3 is not keeping charge. had a parasitic drain test done. It showed the bcm. Had that replaced. Did another parasitic drain test , showing again the bcm.
Possibility's; a\c compressor, ignition, xm\fm radio.
I know about a test thats hooked to the obd and checks modules for operation.
Can ya name that test?
Submitted: 1 year ago.
Category: GMC
Expert:  Gary replied 1 year ago.

what year is this ?

Customer: replied 1 year ago.
07, 3.7
Expert:  Gary replied 1 year ago.

do you know what fuse they pulled to get the draw down ?

Customer: replied 1 year ago.
did myself, think it 12
0r 13. bcm fuse
Expert:  Gary replied 1 year ago.

the 30 or the 10 amp fuse ?

Customer: replied 1 year ago.
10 amp. location of 30?
Expert:  Gary replied 1 year ago.

fuse # ***** is a 30 amp fuse called TCCM

fuse # ***** is a 10 amp fuse and powers the radio and the hvac control module

if it is the 10 amp fuse if you unplug the radio will the draw stop happening ?

Customer: replied 1 year ago.
Sorry, been awhile since I did the test. fuse 14 bcm 10 amp. Pulling the radio is on the list. Hesitation, if the h3 will start afterwards
Expert:  Gary replied 1 year ago.

ok so its fuse # ***** the BCM fuse

if you pull relay # ***** or relay # ***** will the draw go away ?

Customer: replied 1 year ago.
With my memory serving right, all other draws were minimal compared to 14. If you are leading to a analysis of some sort.
I will do another draw test for those
Expert:  Gary replied 1 year ago.

if it has a NEW BCM and it still is drawing too much then we need to see if the BCM is powering modding off and going to sleep after it is shut off

what is the draw in MA reading ? then what is it with that fuse out ?

Customer: replied 1 year ago.
Some info from an old test. fuse in @ 0.065/0.007 fuse out
Expert:  Gary replied 1 year ago.

usually 50 MA is the rule of thumb for a draw and it looks like you are just a bit higher than that

and if you wait 15 minutes it will not drop below that ?

how long will it take to kill the battery ?

and the battery is good with amps and volts tested ( just being sure )

Customer: replied 1 year ago.
Cant recall on the 15 minute marker. I'll do another test
Boosting every day, with a***** One note though, yesterday boosted at shop, 15min ride home and starts up this morning..
Have'nt checked it lately, but the BAT was new
Expert:  Gary replied 1 year ago.

if that draw drops down that far with that fuse out and it has a new BCM the only logical thing that would cause that BCM not to go to sleep would be the ignition switch

that is the only thing that powers up the BCM to become awake then when off and it is not sending power the BCM should time out and go to sleep and when it is asleep the BCM should not running anything at all

Customer: replied 1 year ago.
Thnx, I was once told it was worn out. And had it changed out. But seems loose still with keys and such. I'll get back to ya soon with an update
Expert:  Gary replied 1 year ago.

sounds good

you can always get me back through this post anytime for free with any follow up with this question anytime even after you rate us here at Justanswer !