Hello fellow AZiners! I am trying to trouble shoot why my car (05 TL) is experiencing drained battery issues. Initially I thought my battery needed replacement, so put in an Optima Yellow Top. Then shortly after, I left for vacation for 3 1/2 weeks, and the battery was dead as a nail when I got back. But my MDX started without any issues.

Did the following tests:

1) the voltage across the terminals after a long drive was 12.6 V
2) the charging voltage was 14.2 V
3) the key-off drain is 57 mA. Initially was at 260 mA, but dropped to 57 mA after 45 minutes or so.
4) pulled the remote starter fuses, and still measured around 57 mA.

Now I am completly stumbbed. Spoke to the dealership, and they said if the key-off drain is around 260 mA, a bad HFL module is a very common problem. They said the typical key-off drain should be around 30 mA, and they suggested pulling the power wire from the HFL module and see whether the drain drops even lower. I have a scanned copy of the service manual, but it's missing the page that explains how to remove/replace the HFL module (located at the sunroof controls). The page number I am looking for is 22-451. Does anyone have a copy of the service manual and don't mind posting that page??

If anyone has any ideas on what else to try, please feel free to chip in. Thanks!!

 

There is a TSB that shows how to remove the roof console to get at the HFL Control Unit at:

http://techinfo.honda.com/rjanisis/pubs/SB/B08-057.pdf

Hope this helps.

 

Excellent...I will give that a shot! Thank you very much!

 

How do you test the battery drain power with the key off? I think I have this problem and I want to get it replaced before warranty is up.

 

here you go... once again google is your friend

 

simply take off one of the battery cables (in my case, i took off the negative). using a multimeter, set it to measure amp (A), connect the black (negative) probe to the negative terminal, and connect the red (positive probe) to the battery cable you took off. basically you're putting the multimeter in "series" of the circuit. it might be easier if you use the alligator clips. initally expect a higher draw, but after 10-15 minutes, the draw should drop. the expected draw should be around 30 milli-amps (mA).

 

Thanks... LoL.. I was being lazy.

 

no problem....

 

Hi, I'm sorry for bumping a year old thread, but I was wondering if there's any way for someone to send me the .pdf of the sunroof schematics over email or something.

 

I fixed the TSB link so it works now.

Welcome to the forums.

 

It should be ok for me to just unplug the HFL unit and leave it unplugged? It's actually one feature of the car I've never used since the day I got it.

 

My battery dies after the car sits idle for 2-3 days. I've replaced the battery with an Optimum Red Top and still have the problem. My dealer is a three hour drive away and they won't replace the HFL module unless they can prove that it is the phantom drawing power. I want to disconnect the HFL and test the theory before taking it back to the dealer. I can' access the link in this thread to the service bulletin showing the HFL connection. Can anyone point me to some instructions on how to disconnect the module?

 

Yes, go to this link, post #38. There's a link to a TSB that has instructions on how to access the HFL unit:

https://acurazine.com/forums/3g-tl-audio-bluetooth-electronics-navigation-94/replace-bluetooth-module-791817/

 

I can't get to the instructions - Honda has blocked access to it's TSBs.

 

I say again,click on the link in post #38....

 

Got it thanks. I was clicking on the first link in the thread.

 

Looks like I am in the same boat now. I even moved the battery to the trunk

 

Wouldn't taking the terminal off the battery shut off the HFL unit immediately? So you shouldn't have to wait 10-15 minute right? Just wanted to clarify.