3rd Gen Acura TL Parasytic Draw (not HFL)

[Daniel Froemming]

Good Day All,

I am at my wit’s end with this car and its power draw issues. I purchased a used 2004 Acura TL MT6 with <130k miles in October 2019 and have had many things done to it for preventative maintenance and other minor fixes. The issue I cannot for the life of me figure out is a parasitic power drain of about 420 mA.

Background:
I first noticed the power drain issue after picking up my car from a trusted shop who did my timing work and valve adjustment. They mentioned it needed jumped when they brought it in, and it needed jumped for when I picked it up, so it may be unrelated. After fixing many issues including replacing the driver’s door lock actuator, all the filters, ozone treatment for car interior (had a water leak), replaced my filters, oil change, replaced heater core actuator, re-affixed vacuum line to the front engine mount (this was interesting and made the car far more smooth at idle, probably from fixing the vacuum leak and from loosening that mount), new battery, new power steering pump, and I pulled some wiring for what appeared to be a sub-woofer setup from the previous owner.

Process:
I measured the power draw both at the terminal and on various fuses. I used my multimeter on 10Amp setting and it starts around .85 Amps, and goes down to .53 Amps after about 2.5 seconds, then goes down to 4.2 Amps after about 5 seconds.

I have isolated this to Fuse 7 under dash. Pulling Fuse 7 and running the same test will get me around .02 Amps after 10 seconds, similarly pulling Socket Plug “X” under dash from the relay control box.

I have also done the following to try and narrow down the results:
Removed HFL/HFU in overhead console
Tested after unplugging all connections in Driver’s door
Tested after unplugging all connections in Front Pass door
Tested after unplugging all other connectors (on the front) of the relay control box (Connectors N, R, S, J, K, A, T)
Tested all relays on relay control box (Under dash)
Tested A/C condenser relay under hood fuse box
Tested after pulling various relays and cannot reduce load after relays are pulled (Under dash and under hood)
Unfastened and isolated 2 grounds (G501, G502) independently and tested for change in draw (no change) (Under dash)
Tested after disconnecting rear Navigation box (trunk)
Tested after disconnecting Nav and Radio (head unit and all connections to car)
Tested after disconnecting power sunroof (overhead console)
Tested after disconnecting Wiper controls (took off covers on steering column and removed connector going to light controls and wiper control stalk)
Tested after disconnecting power mirror controls (under dash)

I am unsure what else connects to fuse 7 that can draw this power. I have surveyed the whole under dash situation and found no (obvious) tampering with the electronics other than a tap into a line I have fully isolated. that wire crossed to the passenger side where there was a rat’s nest of extra wire for what appeared to be a cell-phone to fm broadcast device. I have pulled this out of the car entirely.

400 mA is a lot of draw, and it kills my (new) battery in 2 days. I have resorted to keeping my hood popped and slipping on/off the negative terminal for when I want to drive or park.

Does anyone have any recommendations or comments for trying to figure out where this power drain is?

Topic

[Daniel Froemming]

I found it. The NAV unit in the trunk had the fan always running. Diagnosis was to pull into a dark garage and turn off all the lights to look for any light bleed (idea was that there was a light on pulling battery power, 400 mA at 12 volts ~ 6 watts which is the wattage of a incandescent bulb for some interior lights). I didn’t see any lights in the dark (other than the security indicator light), but did hear the fan going. I unplugged the NAV unit in the back and the power draw went down to ~20mA.

I disassembled the nav unit looking for damage or any reason why it may not be working and could not find anything. It won’t eject the DVD under any conditions, so it may be damaged or not repairable anyhow. For now, no Nav system.

[Michael Sackstein]

Scotty Kilmer just made a video on this exact same problem with the exact same car.

Check it out: https://youtu.be/-xNU2ovWB8U

This is the solution to your problem.

[Daniel Froemming]

That video is of a RDX and it uses a newer infotainment system than the 3rd generation TL (mine is a 2004). Also, my backlight for the screen still works, it is the NAV unit itself that is failing. After using the jumper for trying to get into the diagnostic menu, it still didn’t load up, so it needs a new NAV unit according to the official Acura manual.

[b yo]

Hi any updates on the car’s situation? I’ve had the same problem for years, narrowed the problem down to fuse #7, and drove without the fuse. Others on acurazine + reddit reported that the sunroof water drain runs behind the driver’s side fusebox and water leaks could have messed with it. But from my search, most people narrow the problem down to fuse #7 specifically, which can’t be a coincidence. So you’re probably right about the DVD drive is faulty. Did you replace the DVD drive?

[Author]

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