[cnmjr23]

I have a 2007 MDX that has been experiencing a battery drain over the past few months. The dealer has checked both the battery (a 6 month old Costco) and the alternator; both checked out fine. The car is fine unless it sits for two or three days, at which time it is dead as a hammer.

Last night, after charging the battery with an external charger, I hooked up a digital multimeter between the ground cable and the negative terminal of the battery. There is a constant draw of 280 mA, with a 3 to 4 second spike of about 3000 mA every minute. This spike occurs very regularly. The 300 mA constant draw seems very high to me, I would expect something about 30mA. And the 3A draw is off the charts. I have no doubt that this parasitic draw is the cause of my dead battery.

Any ideas? I have researched this and other forums and have come across postings about the HFL, door locks, tailgate lock, and AC relays. The TSB about the HFL does not appear to apply to '07, and I am not having any issues with the locks. Is there an easy way to confirm or eliminate the AC relay as the culprit?

Have same problem. Once the radio/cdplayer/gps screen fuse is pulled. no problem. Had the radio/cd player changed twice. The technician said that there were circuits that branched off from the radio/cd player and he was unable to determine which was shorting. decided to get a portable cd player and leave the fuse out of the fusebox.

 

[Stoyan]

Battery drain, fusen#7, HFL is OK

Hi,

I've done bunch of reading and testing, would appreciate any help on next steps.

History
2012 Mdx with Navigation, 50k miles
This is wife's car. About month ago she saw what she thinks was tailgate relay warning. Disappeared and never showed again.
About a week ago battery died, I read 50k on MDX battery is reasonable, so just replaced it, so it has new battery.
Everything was fine for couple of days, then retrieve of seat/mirrors memory stopped working. Did not work in the morning, then worked if set during the day. Till next morning.
Then car started dying in the morning.

Troubleshooting
I have 2A parasitic draw. Removing 40A back up fuse in engine compartment or #7 (10a, back up) in interior compartment reduces this almost to zero.
Disconnected HFL - no change.

Next steps?
I'm not sure if I need to test battery / alternator, it seems so far tests don't show any problem there?
I could not find yet what's on #7. For now I see I lost navi and stereo, and remote locks(?)
I'd hate to have to go to dealer, anything else I can do to troubleshoot?

TIA!

Hidden battery drain: fixed with door light removal

Wanted to share my story, hoping it would help others who struggled like me. It took me 2 full days to find the malfunctioning module and I haven’t read about this solution enywhere.

So, it probably started when I bought the car 3 years ago. It came with a brand new original Honda battery. I drove it about 6 months and had occasional low voltage. Changed the battery and all seemed well until the winter season. Then I struggled with a few power outages and thought it is just that the battery is too low capacity. 60 amps is really weak for a car this size with so many electrical modules and a big engine to start every time.

A few days ago when I tried to return my new battery under warranty as it started to drop too frequently, the guys at the shop said to me that this brand (VARTA) is very respectful and they really don’t have any complaints with them. After measuring they also said that the battery is OK and can’t replace it under warranty.

That got me thinking – maybe there really is something smelly with my car. HFL was out of the question because I removed it 3 years ago (read this very topic). So before going for a Lithium battery, I decided to investigate. Wired a multimeter (10 amp), locked the car and started with the fuses – one by one. After a few hours, like some other folks in the forum, found out that removing the 40 amp under the hood or the 10 amp back up fuse dropped the current from 180 milliamps to 40 milliamps. And there it began! I read that the BACK UP fuses are responsible for audio, tailgate and internal lighting so I went through many checks and disassembly before I got the answer. First of located the Antenna amplifier which is located under the sub-woofer – didn’t make a change. Then I completely disconnected the tailgate with no luck again. Went through a lot more checks but nothing worked.

This is when I decoded to simulate closed doors (driver’s and tailgate) and look for some misbehavior. Well, I don’t know what made me do this, but I decided to look below the passengers door and there it was! The light below the door was lit even though I pushed the button with a clamp to simulate a closed door + I locked the door manually with a screwdriver while open. Immediately I removed the door’s lamp and the current went down to 40 milliamps, which is the normal draw because I’ve got a CompuStar 800 meter alarm with remote start which is sending signals to the radio remote. Note: I've recently changed all interior bulbs with LED ones so that's why it was 180 milliamps instead of 800 or more.

So if you still have a battery problem in 2022 with the very respected Acura MDX from 2007, please check if you have a lit light after you simulate closed doors.

 

[shamari.zaroonify]

I have a 2007 MDX that has been experiencing a battery drain over the past few months. The dealer has checked both the battery (a 6 month old Costco) and the alternator; both checked out fine. The car is fine unless it sits for two or three days, at which time it is dead as a hammer.

Last night, after charging the battery with an external charger, I hooked up a digital multimeter between the ground cable and the negative terminal of the battery. There is a constant draw of 280 mA, with a 3 to 4 second spike of about 3000 mA every minute. This spike occurs very regularly. The 300 mA constant draw seems very high to me, I would expect something about 30mA. And the 3A draw is off the charts. I have no doubt that this parasitic draw is the cause of my dead battery.

Any ideas? I have researched this and other forums and have come across postings about the HFL, door locks, tailgate lock, and the AC relays. The TSB about the HFL does not appear to apply to '07, and I am not having any issues with the locks. Is there an easy way to confirm or eliminate the AC relay as the culprit?

The player tried to take the disk back as I was removing it. The only way to get it to stop was to feed it a disk and eject it again.

Speed Test​

 

[jeff777]

I have a 2009 MDX that started having the battery drain issue. Finally unplugged the Bluetooth module and that seemed to fix the issue, back down to 20 ma. However, pulling the plug on the module has now deactivated the radio. Is this supposed to work this way?

 

[vinjay07]

On a 2007 mdx, If you confirm the parasitic draw is coming from the radio unit and by removing the fuse.. To fix the parasitic draw, remove the radio/cd unit. Take off the top plate and look for the red and black wire. Cut black wire and tape it up.. Reinstall the plate and the unit and everything should work, including navigation and back up camera.

 

[vinjay07]

On a 2007 mdx, If you confirm the parasitic draw is coming from the radio unit and by removing the fuse.. To fix the parasitic draw, remove the radio/cd unit. Take off the top plate and look for the red and black wire. Cut black wire and tape it up.. Reinstall the plate and the unit and everything should work, including navigation and back up camera.

Only do this if you don’t care about using your cd player anymore.

 

[vinjay07]

On a 2007 mdx, If you confirm the parasitic draw is coming from the radio unit and by removing the fuse.. To fix the parasitic draw, remove the radio/cd unit. Take off the top plate and look for the red and black wire. Cut black wire and tape it up.. Reinstall the plate and the unit and everything should work, including navigation and back up camera.

 

[1tufgt]

To make it even easier just disconnect the 2 ribbons attached to the drive.

 

[vinjay07]

To make it even easier just disconnect the 2 ribbons attached to the drive.

True, didn’t know if anything else would be disabled if the ribbons were just disconnected.. Thanks for clarifying that..

 

[1tufgt]

No problem. Everything else works from my usage.

 

[ogm]

My HFL was drawing but I still had .4amp parasitic draw until I disconnected the xm module (location: https://www.mdxers.org/posts/374207/)

 

[Jxlee0215]

can anyone help. when I remove the radio fuse the draw is gone. When the fuse is in its around starts around 3.50 amps and rest around 0.55 amps. Even with all the radio/navigation harnesses removed from the radio hovers around 0.55amps. not HFL Bluetooth (unplugged) , not amp (removed the fuse-no change). so where else should I be looking?