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Chevrolet Express
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Starts then dies 2003 express 3500

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Old Oct 15, 2021 | 1:24 PM
  #11  
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Originally Posted by not6bucks
Ok traced the wires couldn't find anything wrong
Did you measure any current on it?

Originally Posted by not6bucks
could the bcm actual be causing the short?
it could , but likelihood is low. Especially since everything else is working.

Do you have any aftermarket accessories? Anti-theft, remote start etc.
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Old Oct 15, 2021 | 5:24 PM
  #12  
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Originally Posted by mountainmanjoe
Did you measure any current on it?


it could , but likelihood is low. Especially since everything else is working.

Do you have any aftermarket accessories? Anti-theft, remote start etc.
At one time there was a gps tracker from Verizon on the van but that was removed a year or more ago, was thinking that might be it too but I can’t seem to find where it was sliced in
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Old Oct 18, 2021 | 4:27 PM
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Originally Posted by mountainmanjoe
Did you measure any current on it?


it could , but likelihood is low. Especially since everything else is working.

Do you have any aftermarket accessories? Anti-theft, remote start etc.
ok I found a ground short at the bcm brown wire for anti theft when unplugged from bcm no ground short but it is plugged in ground short, is the bcm causing this or am I just going crazy.

got the rear tail light to work changed bulb and it works again bulb looked fine when compared to the new bulb.

Before I spend 200 on a bcm would like to know if that could be it.

Last edited by not6bucks; Oct 18, 2021 at 4:45 PM.
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Old Oct 18, 2021 | 8:19 PM
  #14  
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Originally Posted by not6bucks
ok I found a ground short at the bcm brown wire ...
Did you fix the short? what caused it?

Originally Posted by not6bucks
would like to know if that could be it.
so, does it start now? Is it still blowing fuses?
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Old Oct 18, 2021 | 8:59 PM
  #15  
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Originally Posted by mountainmanjoe
Did you fix the short? what caused it?


so, does it start now? Is it still blowing fuses?
I don’t know what causes it, unplugged from bcm no short, plugged in it has a short.

no start still blows fuses number #19
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Old Oct 18, 2021 | 10:05 PM
  #16  
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Originally Posted by not6bucks
no start still blows fuses number #19
I meant when you unplug the tan wire (antitheft?)
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Old Oct 19, 2021 | 8:31 AM
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Originally Posted by mountainmanjoe
I meant when you unplug the tan wire (antitheft?)
Nope when I unplug that wire from the harness it still blows # 19
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Old Oct 19, 2021 | 1:16 PM
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That's thoroughly confusing because you said
Originally Posted by not6bucks
when unplugged from bcm no ground short

Anyway, unplug all the BCM connectors and measure the resistance between these wires and ground. It should be at least 2 ohms:
Battery Positive Voltage, Ignition Voltage, 5V or 12V Reference, any supply voltage
BCM pinout: 2003 Express Body Control Module - Chevy & GMC Vans

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Old Oct 19, 2021 | 3:03 PM
  #19  
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Originally Posted by mountainmanjoe
That's thoroughly confusing because you said



Anyway, unplug all the BCM connectors and measure the resistance between these wires and ground. It should be at least 2 ohms:
Battery Positive Voltage, Ignition Voltage, 5V or 12V Reference, any supply voltage
BCM pinout: 2003 Express Body Control Module - Chevy & GMC Vans
This is what I got with everything unplugged from BCM
Plug C1= (A 2.5) (E 3.3)
Plug C2= (B3 74.2) (B6 0.3)
Plug C3= (B6 0.3)
Plug C4=( A4 47.5) (A5 0.5)
Plug C5 = (F0.8) (E 1.1)


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Old Oct 19, 2021 | 6:50 PM
  #20  
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C5 looks suspicious. Try unplugging that.

I'm not sure why you measured grounds and signals. Like I said you need supply voltage pins.
C1 - C,D,F
C2 - A11,A12,B8,B11
C4 - A3,A4 etc...

Oh yah, and always disconnect the negative battery cable before poking around in the electricals.

Last edited by mountainmanjoe; Oct 20, 2021 at 3:32 AM.
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