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Discussion Starter #1
Discovered after recent rains that the floor behind the driver's seat was full of water - obviously well known problem in this forum! Took out the carpet, got rid of the water, took out the CCM and after cleaning and drying it appears to be fine (at least now the windows work, no more spurious lights in the cabins, no more honking from the trunk, etc.), except that the car will not start (not even turn) with a brand new battery! So perhaps the CCM suffered more serious damage than anticipated and it's time for a new (used) one!
However, the strange thing is that as soon as the battery is connected there is a humming noise from the engine compartment.
Disconnected the CCM, key out of the ignition, all doors closed, there is still a humming noise as soon as the battery is connected, and there is a current draw of 1.7 amps! Checked all fuses and they appear to be ok. I was going to bypass relay #12 to at least try to start the engine, but not with such a current draw!
Any ideas or advice as to what else I should be checking?
There was obviously a significant amount of water under the battery (clogged drain) and tried to follow the path of the water into the cabin, but cannot see anything else that is obvious!? Under the ECU perhaps?
Thanks in advance.
 

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If you have automatic transmission, the TCM is under the passenger's seat. Any water there?

Beyond that, try to figure out what's humming. There are quite a few electrical loads still live with the key removed, so there's no single obvious thing to check, particularly since the hum is under the hood, not in the cabin.
 

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Need to unwrap the entire wiring harness for the CCM as far as you can. Very common to have to replace broken and corroded wires and factory splices.

If all that checks out you may have a dead CCM. Check each wire carefully. Agree with checking the other footwell if you have an Auto also
 

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The V6 has an after-run coolant pump above the alternator (below the passenger side head). It will run for a little while when you connect the battery, even when cold. Look for coolant moving in the small line at the coolant tank. It should turn off after 15-30 seconds or so.
 

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Need to unwrap the entire wiring harness for the CCM as far as you can. Very common to have to replace broken and corroded wires and factory splices.

If all that checks out you may have a dead CCM. Check each wire carefully. Agree with checking the other footwell if you have an Auto also
A major wiring short and meltdown is what finally killed my 1996 A4. Replacing burned, melted, or corroded wiring can be quite the adventure, depending on where the problems occurred.
 

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Discussion Starter #6
Thank you all for your suggestions; it’s a manual, so no TCM, which saves me having to look under the passenger seat. With the CCM still completely disconnected I took out all fuses and connected the battery. This time there’s a different humming noise, it draws slightly less, 1.4 amps, but only for 3-5 seconds, after which the noise quits and the current drops to an acceptable 40 mA. Perhaps this is the coolant pump that PZ was talking about... Now the plan is to insert the fuses one by one and figure out which circuit is causing the humming. Will also examine the harness and all splices from the CCM.
 

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I think the electric coolant pump runs off of the fan controller under the front frame horn, just behind the radiator.
 

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Discovered after recent rains that the floor behind the driver's seat was full of water - obviously well known problem in this forum! Took out the carpet, got rid of the water, took out the CCM and after cleaning and drying it appears to be fine (at least now the windows work, no more spurious lights in the cabins, no more honking from the trunk, etc.), except that the car will not start (not even turn) with a brand new battery! So perhaps the CCM suffered more serious damage than anticipated and it's time for a new (used) one!
However, the strange thing is that as soon as the battery is connected there is a humming noise from the engine compartment.
Disconnected the CCM, key out of the ignition, all doors closed, there is still a humming noise as soon as the battery is connected, and there is a current draw of 1.7 amps! Checked all fuses and they appear to be ok. I was going to bypass relay #12 to at least try to start the engine, but not with such a current draw!
Any ideas or advice as to what else I should be checking?
There was obviously a significant amount of water under the battery (clogged drain) and tried to follow the path of the water into the cabin, but cannot see anything else that is obvious!? Under the ECU perhaps?
Thanks in advance.
My driver side carpet gets wet due to the lower door seal. It runs down where the door meets. I have not looked yet for a new seal. Perhaps the door needs a bit of alinement. Not sure. That has caused the small lights at the shift knob, automatic, to stay on. Wetness is a pain inside.
:(
 
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