luiskeniosis

Hello! I'm a student on my first year of college, and I have an 2009 RDX with 147k miles. I'm not a mechanical expert, but my dad worked on cars for a while so I take his advise when it comes to stuff like this. I've been experiencing electrical/starter problems for the past week or so, let me explain:

A few weeks ago, I tried starting the car, but when I turned the ignition, my dash and speed dials flickered and gave out, and the car wouldn't start. I figured it was because I left a light on or something and my battery died, so I charged it, and the next time I tried starting my car, it worked. I called my dad and told him about it, and and he told me to do a simple multi-meter test to see the battery's output, to see if it will happen again. I did and it was around 11.3v with the engine off, and 12.7v with the engine running. He said this was a problem, and after a quick google search (LMGTFY) I confirmed it was an issue. The battery is less than a year old (installed on July 2018) so we made the call to get a new alternator from DB Electrical (Manufacturer Part Number: AND0485), and while we were at it, we decided to get a new Dayco drive belt, since we would be needing to take the old drive belt off anyways.

After installing the new alternator and drive belt, then taking a drive around the block, the battery output still stayed at around 11v with the engine off, and 12-13 with the engine running (but the car hasn't failed to start again). We decided to have professionals look at it, we got the battery tested at Walmart (it's where we bought the battery and we have a warranty if it is broken), and they said it was fine, then we tested both the new alternator and the battery at our local repair shop, and they said both parts were working (my dad did this without me so I don't know the details but he said that when the alternator was tested, it output 14v). The shop did recommend a new starter, and they said something like "the starter is using too many volts because it's worn, so it may be causing the problem", which sounds like them trying to make money, but it's an old car, and i'm going to need it to be reliable for college, so we shelled out the money to get it replaced anyways.

So after spending $650+ on parts and labor, the battery still outputs low voltage when tested. I've been looking around the internet throughout this whole process and looking for other solutions to the problem, but almost every website just recommends getting a new battery/alternator, both of which apparently were working in my car, can anyone give me suggestions? Thanks in advance

Other Info:
-There has never been a warning or indicator light on the dash throughout this whole process.
-Alternator and starter are both less than a week old, less than 50 miles driven on them.
-Battery is less than a year old, 3-4k miles on it.
-Old drive belt shows no sign of uneven wear (idk if this is relevant).
-Car has only failed to start once, everything we've done is in hopes to prevent it from failing to start again, we didn't know for a fact if anything was broken when we replaced parts, but better safe then sorry right?

Tomtwtwtw

Batteries can sometimes just go bad prematurely due to some other issue, I would still recommend replacing and checking voltage again. Don't assume that just because it's young, it's good - they can be defective from the start like any other part. Generally, an alternator that is outputting low voltage will throw a light in your dash, but a bad battery will not.

CSmoney28

Did you check the HFL and also is anything aftermarket on your RDX like an alarm?

thoiboi

Get a new battery.

luiskeniosis

I have not checked the physical HFL circuit board, but HFL works, connects to my phone, allows me to make/answer calls, microphone and audio both work. Also, i have no aftermarket parts.

luiskeniosis

I will be getting a new battery this weekend, will come back here if there is still a problem. Thank you all for your help

Altair

2008 rdx, base, charging voltage

This is my idling voltage, I presume original alternator and starter.
Using Torque on android Samsung phone.

Battery is over 2 yrs old, maybe 40000 km mixed driving on it since installing it, probably not in good shape by now as it shows a surprisingly low @11.7v before turning the engine on.

I did have some recent trouble after NOT running the car for less than 48 hrs. As it wasnt v cold outside, I chose to disconnect the HFL Bluetooth phone module and seems to have addressed it so far (just unplugged and kept it there, did not remove it from under the shifter/center console).

Look up state of charge for car batteries by temperature and do the math for your situation, before and after the battery charge. You may have something else lurking somewhere to explain how the 14v tested new alternator to show only 12.7v idling. Do your own test should be cheap, 10$ multimeter perhaps?

Good luck with your studies!

Altair

My HFL was not showing any signs of problems either, but seems to have cause starting problems after 1-2 days without any trip around. Once disconnected, no more problems for about several weeks now, that's why I blame it.

Took some 10' to figure out how to get my hand on the connector without removing the center console carpet siding from the passenger space.

luiskeniosis

Where was the HFL module? This sounds like it could be my problem, I want to disconnect it (i rarely use it) and see if it fixes my issue. How do you remove it?

Altair

I searched for "HFL" with advanced (acurazine specific not Google), restricted it to first gen RDX forum only and it's subfolders

FOUND "https://acurazine.com/forums/1g-rdx-problems-fixes-160/help-how-do-i-remove-hfl-module-lost-3-batteries-967967/?highlight=Hfl"

My side panel was a single piece, had to remove its fixing nut. I did not have the patience to remove so I snuck my hand over/between it's top and the console and unplugged the module. Figured not worth the time to remove it in case was something else. Took slightly longer to fit nut back, my seat being manual did not go back far enough to clear an opening.

Also found this very informative
"https://acurazine.com/forums/1g-rdx-audio-bluetooth-electronics-navigation-159/rdx-battery-drain-all-known-issues-976172/?highlight=Hfl"

Cheers

luiskeniosis

UPDATE: Altair's first reply got me thinking. My multimeter was really cheap and old, I found it in my garage years ago, and could be inaccurate, so I got a new battery today to test it. I used the multimeter on the brand new, fully charged battery with the same old multimeter that I tested my original battery with, and sure enough, it gives a false reading of 11v. Just to confirm, I bought a new multimeter, and tested both my old battery and the brand new one (with the engine off). I just got. 12.7v on my old battery, 12.5v on the new one.

In short, a faulty multimeter reading caused all of this.

What I think happened, is our starter was failing, and caused the initial starting failure. We assumed it was a battery issue, and got a new alternator, and the rest followed. However, we did replace the failing starter, which should prevent any future problems.

Will let you guys know if anything else happens, thanks for all the help, especially Altair for indirectly solving my problem!

Altair

You are most welcome!

Guess that is what university is for: to get one thinking, test hypothesis ... and tools ... is standard operating procedure 😁

Good part is you may have taken care of the starter and alternator for next 10+ years.

Heads up: a new battery WILL mask a HFL discharge (if there is one) longer than a bad battery, so may want to test the standby draw with the new multi meter before you call it solved. You know, test your hypothesis...

"https://m.wikihow.com/Find-a-Parasitic-Battery-Drain"

luiskeniosis

I will be checking all fuses this weekend, thank you for your help!

CSmoney28

Glad you got the fix!