Greetings all,

My mom has the car listed in title. It's a pretty basic model, but with the 6 cylinder. It has about 120K miles on it. It now has some sort of parasitic drain situation that kills the charge after a few days sitting. The battery is new.

I have verified that there is indeed this drain of 410 milliamps, although when it first registers on the meter it shows about 620 milliamps, but quickly goes to 410mA. It is constant. I traced it to the large, 40 amp fuse in the under-hood box that allows current to go to fuses 9,10,11,12, and 13 in the junction box at the passenger side dash. I pull the 40 amp (Fuse 54.) in the underhood box and the draw disappears. Of the 5 fuses in the passenger box, only the #13, 7.5 amp fuse kills the draw.

Based on what I saw on the inside passenger box lid, I thought the #13 fuse was only integral to the back-up lights and clock. That was wrong. I guess allows power to a lot more than those. Before I attempt to trace this any further, or hire a pro to do it in order to protect my old back, does anyone have any ideas on this? Again, 410 milliamp parasitic drain on 1999 Accord with V6. Many thanks ahead of time. Cheers.

 

It powers a lot of items. PCM, Heater control panel, security indicator, door multiplex unit, gauge assembly, clock, climate control unit, driver's side multiplex unit, and passenger side multiplex unit.

 

Thanks, @PAhonda . I found the page in the shop manual that shows just what you say. I'm thinking it's above my electrical troubleshooting pay-grade. It looks like it's going to a pro. Bending over low cars like this one, and contorting under the dash is something I can't do anymore.

BTW, something I didn't mention, which I can't see suddenly giving a problem, is that I unhooked the aftermarket alarm "box" that was tucked under the dash about 7 years ago because I couldn't get the horn to stop. The harness to it has bee unplugged that whole time. And, as I said, it is an aftermarket alarm, a Viper of some sort. Anyway, if that tells anyone anything useful, I'd appreciate an additional response. Otherwise, I guess it's bite the bullet and take it to a good mechanic. At least I can save them 1/2 hour of tracing. Whether or not they acknowledge that in the price is uncertain. Thanks again. Cheers.

I recalled, and verified, that the cluster was removed to "reset" after the alternator was replaced 12 years ago. I'm not sure if that was unusual, but it is tied to the cluster. In addition, when I had the fuse #13 pulled thinking the car would drive without it two days back, when I turned the key to start the car (Unsuccessfully...nothing, despite full battery charge.), I saw the speedo briefly snap to the right and go right back before nothing at all happened. That what made me think of the speedo. That and the mention of the cluster above. Maybe residual power releasing from a capacitor or something? Or maybe it tells someone knowledgeable here something useful?

 

Once you are down to the items in the circuit, then you need to unplug each item to further narrow down the cause. The tricky part is the MICUs are mini computers/control modules, so unplugging a door lock could reset a bad MICU.

I don't know how the old alarm is wired, but it could be your culprit. If it was wired for power on a line that is fed by fuse 13, the old alarm control unit could have some kind of short and is drawing a current.

If you had access to a thermal camera, you could look to see what components/areas remain hot after the car is shutdown overnight. Most folks at home don't have access to a tool like this at home.

 

Thanks, @PAhonda . Would the old alarm box under the driver's dash be suspect even though the large plug, and I believe the only plug, is disconnected from it, and has been for nearly 10 years?

I don't have a thermal camera, but do have one of those lazer thermometers. I suppose having a larger field of view would be much better with a thermal camera. I wonder if infrared goggles would work? That's an interesting idea. It may be all rather moot, as I dropped the car off at a professional who seems to be capable and trustworthy. I'll check back with a report to how that ends. Thanks again. Cheers.

BTW, on the way to the mechanic, I noticed that the lights weren't lighting up on the climate control center. I doubt that the headlights have to be on for these to light, so maybe that is the source of the problem. I gave this info to the mechanic.

 

I wasn't sure how the alarm was disconnected, so it likely isn't the culprit.

It could be the climate control/radio based on your description. The only way to verify is to unplug it while you have the amp meter hooked up.

 

Thanks, @PAhonda . I might just try that before I bring it to the next guy in line, an auto electric specialist. The general mechanic told me to come and pick it up without it being repaired. I guess he looked at the MICU issues, etc., and figured he didn't want to get into it. At least he's not charging anything for looking at it.

I'll check my factory manual to see how to disconnect the climate control assembly. Otherwise, I'll see if there's a fuse that controls just it, I'll pull it. I'll keep reporting back on this stuff. I appreciate your help, and know how it is when someone asks such questions and leaves good folks hanging while they wait for what might be a useful resolution. Drive-by queries. Cheers.

Edit: The service manual points to fuse #3 on the driver's side in the circuit for the heater controls. When I pick up the car in the morning I'll bring my meter, pull the #3, and see if the drain disappears.

 

I pulled the number #3 fuse in driver's side box and the draw stopped. So I guess I can be pretty sure that this is where the issue lies. I'll look into removing the center dash trim so I can remove the control unit. In the meantime, the computer has set the heater to "On". Fortunately, it's pretty cold right now so it's not too obnoxious to have it blowing hot air. If it's a PITA to get to the control unit, I may end up taking it to the auto electric place to have them do it anyway. They are supposedly electric and A/C specialists, so it should be in their wheelhouse.

Any comments, tips, etc., on getting that control unit removed would be appreciated. Cheers.

 

Well, I ended up pulling the control unit, taking it apart to get to the back of the circuit board, and re-soldered a bunch of capacitors and resistors. I have an old stereo microscope that allowed me enough working room, etc. There were a few solders that looked iffy, but I soldered all that I felt I could safely do without destroying paths, IC's, etc. I had watched a guy on youtube who had a different problem, but figured it was worth a shot. It was. Bugger is back together with no parasitic drain and the lights on unit came on, A/C kicked in when activated, etc. I think that's a wrap.

So, 410 mA parasitic draw problem was tied to a bad climate control unit. My mom said, "I guess you saved me a couple of hundred dollars.". I told her that a shop would have charged $500 plus, as it's doubtful that they would have bothered with the re-solder. But he, it worked. Thanks for your help @PAhonda . Cheers.

One thing to note is that if you do take the back of the unit off to get to the circuit board, be very careful when you rethread the screws during reassembly. I was shocked that they just didn't want to go in well without breaking the plastic they were screwing into. If I did it again, I'd spray some teflon or something on the screws to ease things a bit.

 

Glad that you figured out the issue and sounds like it is fixed. Thanks for posting the outcome. A lot members don't update us with the final fix.