2005 Acura RL Battery Goes Dead While Parked

This 2005 Acura RL came in with the complaint that the battery would go dead if the car sat parked for more than three days straight. The battery had been replaced a couple of times already. I first connected a jump box connected in parallel to the battery before installing  the meter as shown below. You cannot see it but the black lead is installed in the COM socket and the red lead is installed in the 10A socket. The dial is set to read DC amps. After an hour there is still a .23 amp drain on the battery.


Because I have been down this road before I consulted a wiring diagram first to see which fuse supplies battery power to the HFL module (Hands Free Link). It turned out to be fuse number 5 in the driver’s side under dash fuse box. Pulling the fuse removed the drain. Pulling the fuse will also activate the anti theft feature in the radio so do not pull it or fully disconnect the battery unless you have the reset codes. 


Testing across the fuse terminals had shown a 2.3 millivolt drop confirming there was a drain on that fuse. Sorry that I could not take a picture of this test. Just not enough room and awkward angles to work with.


I looked in my component locator system and found that the HFL module is located behind the right kick panel area. I started by pulling down the passenger side underdash hush panel. It is just snapped into position with two alignment pegs at the firewall edge.


Disconnected the harness connector for the courtesy light and removed the panel.


Lifted the inside edge of the rocker trim panel to begin releasing the clips.


Worked my way from the front to the rear of the trim panel.


Pulled the door seal away from the kick panel.


Pulled the kick panel loose from the body. Note the two clips that secure the panel to the body. Those rarely come out and stay in the panel. I had to remove those separately and reinstall them into the kick panel.


Now if you look above the passenger side interior fuse box location you will see the lower left corner of the HFL module. It is secured to the body with one 10 mm nut which is a little bit of a pain to remove. Not even sure if it has to be removed to disconnect the green harness connector but I wanted to make sure you had a good view of the actual part.


Since the battery had been connected during all of my testing the HFL module was warm to the touch.


With the HFL module disconnected the standby drain dropped to an acceptable .03 amps.


As in most cases the vehicle owner never uses that system so they elected to leave it disconnected. I did leave it installed in the car but electrically disconnected.

3 discussions on “2005 Acura RL Battery Goes Dead While Parked”

  1. I have the same issue with my 2006 Acura RL and I did disconnect HFL module but recently, specifically on the rainy day my radio locks up on HFL! How can it be with module is disconnected? Why am I getting this “phantom” HFL display? I can’t switch from it to my Radio’s AM, FM, CD or XM. Tried to pull the radio fuse out and plug it back in… No results, still locked on HFL display. The steering wheels controls are not operational for HFL, because module is disconnected. Please help! Even Acura tech is lost and has no answers for me, besides assuming that my radio is bad. Is it coincident that it happed twice during the rainy day? I have no traces of water on the passenger side where HFL module located and where harness is been disconnected. I am lost, very frustrating
    Any comments or suggestions are welcome.

    1. The first thing I would try would be to reconnect the HFL module and see if the issue goes away or at least can be turned off with the controls. Since you mentioned it happened on a rainy day I would suspect a water leak into the dash somewhere. If reconnecting the HFL does no good I would recommend keeping the car garaged and dry for a few days to see if the problem self corrects that way.

      1. Just reconnected everything back including HFL module. Controls are now operational but can’t switch. Went to factory setting by pressing MAP/CANCEL/MENU at the same time. That gives me option to check the unit (Radio, GPS, Display…): everything was OK and green, except under DVD showing as an error. I don’t know, may be it is normal, because the system diagram in factory setting showing all green boxes. I can see my GPS map but still locked on HFL (can’t switch to CD, AM/FM, XM). HFL connected to my phone and keep stating HFL system is okay. Car is in garage and has no moisture anywhere behind the radio unit or down on the floor mats. May be the rain just a coincident… May be the radio unit is no longer works properly. I am lost, pulled the Radio fuse out to prevent battery issue in the morning. Will be talking to Acura tech who originally pulled out my old USA SPEC system for connecting iPhone to a radio via wire for music, I used that for years with no issues. He assumed that radio got locked due to aftermarket system (HFL was already disconnected at that time by me due to occasional HFL lock and battery drain).

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