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Parasitic power draw?

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Old April 17th, 2018, 1:40 AM
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Default Parasitic power draw?

Parasitic power draw?
Car is a 2007 Saab97x 5.3i same as Trailblazer

My battery is being drained in around 5 hour period.

inserted the amp meter into the negative batterys circuit found a 3.3 amp draw.
pulled every fuse one at a time and reinserted each fuse the only fuse that reduced the draw significantly was the
radio fuse #41 (radio plays however the NAV display in nonefunctional) interior FB went from 3.3amps down to 1.3amps some other fuses made like 1/2 a amp difference I'm thinking still too much of a draw.

however during testing w/ drivers door front/rear open would that alone be worth 1.3 amps of draw? Is there a way to have the doors physicalley open so I could pull fuses

but electricalley fool the computer to think the door is closed?
I sean people put tape over the door button switch to fool the computer the door was actually closed? I don’t see such a button.

edit: the interior dome lights didn't come on w/ doors open during testing.

I assume I could simpley close door to see if the opened doors are worth 1.3 amps draw.
Thanks for any usefull tips.
TB

Last edited by the Brain; April 17th, 2018 at 1:43 AM.
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Old April 17th, 2018, 9:20 AM
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the door ajar switch is in the door latch. you could flip the latch closed with a screw driver and work with the door open.
However, start with the door closed and at the underhood fuse box. All the power for the in cab fuse boxes come from the underhood fuse box.
-when you pull a fuse, leave it out. re-installing it can wake a module up.
-use a battery master switch. https://www.princessauto.com/en/deta...ch/A-p4210962e
.....it may take 20 minutes for all the modules to go to sleep after disconnecting the battery and putting the meter in series. Your meter may time out.
-unplug all aftermarket accessories, phone chargers, remote start etd.
normal draw should be 10m amps. 50 mamps is acceptable.
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Old April 17th, 2018, 10:50 AM
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w/ door open it adds 1 amp. to readings I am getting erroneous readings.

how long should I leave a fuse out? I've been reinserting after 5 seconds it seams like I have been turning the meter off then back on after reinserting the fuses to verify draw amount.

I have only tested /removed the spade fuses haven't removed the square larger fuses or even a radio related relay, actually looked for a radio relay on the printed fuse box didn't see such relay.

anyway my findings are after reinserting fuse except for radio are now mysteriously down to a .14 amp draw I'm thinking is normal for the burglar alarm, that w/ door closed. maybe I cleaned the ternimals when removing and reinserting fuse.

I have also observed that the amp draw takes time to reduce around 20 seconds after I close door.

not sure if I fixed anything except for removing a problematic radio.
Thanks for advice
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Old April 17th, 2018, 9:27 PM
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-working with the door open keeps the bcm awake....unless you flip the door latch.
-if you cycle your meter on/off and don't use a masterswitch...it awakens all the modules.
-no, 140mamps or 0.14amps is excessive. aftermarket alarms add 30mmps to the vehicles draw. factory alarms add nothing.
-you keep the fuses out untill you find the fuse that is causing the draw

Last edited by tech2; April 17th, 2018 at 9:29 PM.
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Old April 18th, 2018, 1:55 AM
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Originally Posted by tech2 View Post
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-no, 140mamps or 0.14amps is excessive. w
so this 0.14amps will still discharge battery overnight or shorter period of time?

what is a normal draw?
thanks TB
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Old April 18th, 2018, 9:32 AM
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the time to dead battery depends on the capacity of the battery and the amount of draw. if i had to guess; 140 mamps may take a week of sitting before you get a no start. normal draw is listed in post 2
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Old April 18th, 2018, 9:52 AM
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There’s a few things I skipped over during my testing like letting car sit w/ everything turned of for the hour to make sure the modules where asleep.

I also had the key FOB in very close proximity my poctket.

I was suspicious of the radio it has a ribbon cable/interface that is burned it's probablly shorted inside the none functioning NAV part of radios display attach image.
This is the circuit w/ the draw. Draw started out as 3.3amps then dropped to 1.3amps after removing radio fuse all this w/ doors open (no dome lights where on) then I close the doors reading is reduced to .13amps.

So doe’s this sound normal? Safe to reconnect battery and leave car unstarted for at least 5 hours then check batterys voltage to see if it’s still draining to quickly.

Edit: I have been reading/researching and found these trailblazers even the expensive SS
Have power drain issuses.
Thanks so much for helpful advice hopefully the car can be releided on. will report back w/ results.
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Old April 19th, 2018, 7:24 AM
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removed radio and it's fuse
battery went from 12.55VDC last night down to 12.42VDC this morning, over a 12 hour period of time.

I only have one key can my key FOB key section be duplicated as a regular none electrcal key?
Thanks TB
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Old April 19th, 2018, 11:08 PM
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Originally Posted by the Brain View Post

I only have one key can my key FOB key section be duplicated as a regular none electrcal key?
Thanks TB
Not sure what your asking. Is the key and fob one piece or 2 separate items? post a pic of the key and fob
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Old April 20th, 2018, 10:10 AM
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update on the battery drain after a two night period of time of being unstarted the battery is down to 11.9VDC is this normal or is there still a drain? if yes how low can a battery go down and still be normal?

edit" yesterday which was the beginning of day two I made the mistake of opening the liftgate just to get stuff out then closed right away.

the FOB has the key builtin like this
https://www.remotesremotes.com/produ...SABEgK_h_D_BwE
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