Chasing a parasitic draw
06-16-2018, 08:23 AM
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Chasing a parasitic draw The battery won't hold a charge on my 02 WS6. It went from holding for a couple of weeks to now just a couple of days. I've been trying isolate the draw with a multimeter. Anyway, I noticed the radio will come on but won't change stations or volume control. This morning the battery is dead but I heard a hum from the radio.....pulled the fuse and still have a hum! I assume this is my power draw. Any ideas? Bad radio? I searched and found some info about the solder joints in the BCM? This is a zero mod car with 15k miles so no aftermarket electrical items.
06-18-2018, 07:22 AM
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The BCM fix is very specific - it's for the Retained Accessory Power (RAP) circuit which powers the radio and the windows for several minutes after the ignition is shut off or until a door is opened. The fix is for bad solder joints which cause the radio and windows to intermittently stop working. It doesn't apply to a current draw or hum.
Which fuse did you pull? The radio has two - RADIO is ignition controlled and powers most of the radio functions while POWER ACCY is constant (battery) power for the clock, station memory, and CD eject functions. Rather than pulling the fuses, you might want to pull the radio. It's quite simple... pull off the trim panel, remove three screws using a 7mm socket, and pull the radio out to unplug the connectors. That will tell you if the radio is the source of the draw. If the hum continues after unplugging the radio then it's likely the Monsoon amp. It's under the right quarter trim panel in front of the spare tire. Unplug it (or pull the RADIO ACCY fuse) and see if the hum and the power draw go away.
Which fuse did you pull? The radio has two - RADIO is ignition controlled and powers most of the radio functions while POWER ACCY is constant (battery) power for the clock, station memory, and CD eject functions. Rather than pulling the fuses, you might want to pull the radio. It's quite simple... pull off the trim panel, remove three screws using a 7mm socket, and pull the radio out to unplug the connectors. That will tell you if the radio is the source of the draw. If the hum continues after unplugging the radio then it's likely the Monsoon amp. It's under the right quarter trim panel in front of the spare tire. Unplug it (or pull the RADIO ACCY fuse) and see if the hum and the power draw go away.
06-18-2018, 06:42 PM
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Thanks for the reply. I pulled both fuses, however once I jumped the car and let it run for about an hour, shut it off and now no hum from the radio. Also the radio functions normally now. So the radio seems to have a problem but I'm not sure its related to the draw. Cars been sitting for about 24hrs and has gone from 12.57 volts to 12.36 volts. Doing a parasitic test I can't see but about .30 volt draw...which is about normal I think. So the draw seems to be intermittent. I am going to pull the radio and see what happens.
