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Power Dies On Ignition and BCM Sounds

K

kirmie

New member
I'll try to sum this up. When I turn the key to start the engine everything dies. Power is completely gone. Disconnecting and reconnecting the battery or waiting long enough (hours) and it gets power back to do the same thing again. All main and glove compartment fuses and relays have been tested. Relays tested for both continuity with 12V and no continuity without. The battery and cables are only a month old and there are no shorted wires under the dash or going to the shifter. I even cleaned off the connections as well as the ground to the frame.

OK, on to the good stuff. Interior lights work fine but when I push the lock/unlock buttons I get sounds coming from my BCM. Slightly different sound for each. I also get sounds for the seat moving toggle and my remote does nothing. Thoughts on the issue? I've completely disconected the DRL's and tried one by one on fuses to no avail. I'm thinking it's the BCM or the ignition switch or whatever it's called (blanking right now on that). Ideas? I've managed to remove the BCM and there are no burnt spots or blown capacitors inside.

Edit: Probably should mentio its a 2000 GTP and I have have an aftermarked starter just to make things more complicated.
 
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Well, is there any loose connections? Corrosion anywhere? I would check all my connections. Make sure battery is not bad.
 
Any other ideas? I don't want to be going after a new BCM if the problem is something like my ignition.
 
Tried a new BCM from a 2000 GTP and no luck. BCM still makes click on lock, click-like beep on unlock, and bzzzzzz while hazards are on. No start or radio with key in though I'm not getting the power to disappear when I turn the key. Just nothing happens and the key locks in.
 
Sanded every ground connection that I could find, reconnected everything I could find, sanded and reassembled the battery terminals, etc. Something I did worked and got it running so I attached a trickle charger and the next time I tried to start it insta-died again.

I have a couple theories. 1 is that the charger somehow was raising the voltage of the battery too high and causing a circuit to break. The other is that a circuit breaker is bad. Any ideas? When the car went to start it shut off the power to everything again. No interior lights or anything so something is stopping the power early.
 


You SURE your battery is good? Check the voltage of the battery (with no electrical load); it should be about 12.5 to 12.7 volts for a fairly new battery. Any lower than that and you might have issues. The battery on my '05 GP failed fairly suddenly at only 2 years old just the other day; the NAPA store verified it was a bad battery - they put a new one in and no problems now. But I had symptoms somewhat similar to yours before it went out.
 
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