Parasitic Draw is draining my battery. I found the circut, now what?
 

Hi,
I have been having an issue with my battery dying when I let my coupe sit for two or more days. I originally thought the battery was the problem since it was the original battery. I now realize that the battery was not the real reason the battery was not holding a charge. After doing some searching around on this site I found that others had a similar issue and called it a parasitic draw. The only way to diagnose the problem is to take a 10a volt meter and test the voltage being drained from the battery as it sits. This is a PITA job. With the volt meter being the connection between the battery neg and the neg cable in the engine bay you can get a reading from the volt meter. Mine is 5.4mah i believe which is draining the battery fairly quickly. With the volt meter connected I propped it up on my windshield and sat upside down in my driver seat and pulled one fuse at a time. Unfortunately the fuse for the problem was not coming from the fuses in the driver side panel. I then moved to the fuse box in the engine bay and finally found the circuit thats causeing the draw. When I pulled the "RADIO" fuse the reading on the volt meter dropped much lower. I also kept the fuse pulled for a few days just to make sure that the battery kept plenty of its charge.

The problem is that now that I know its the "radio" curcuit causing the problem I dont know what else I can do to trace what is failing on that circuit and causing a draw. Im a member of infinitihelp.com and was able to download the service manual but it looks like the electrical section ends at the navigation section. How can I find out everything on that circuit, or better yet trace the problem???

I know there are some wiring geniuses on this site that know where I can find the answers.

I have an 03 coupe it came with the bose system and no Navigation.

Try disconnection the Bose amp when the car is left sitting. If this is your problem then either replace the amp or add a power on relay of the proper size to isolated the amp with the car shut off. It sounds like a known issue with the OEM sound system where either the Bose amp has an internal issue or the head unit is not properly handling the amp on line.

Bose amp was not the problem. Does anyone know where I can find a diagram of everything on the radio circuit?

It took a year to find that out?

Anyway, you can find a diagram of everything here:
http://www.psedog.com/cars/fsm/g35/coupe/

Just go to your year from there and the "av.pdf" is what you'll be looking for.

A 5.4mA draw will NOT kill your battery and is actually extremely low for any car, let alone the G. Anything under 50mA is generally considered acceptable for idle current. The last time I checked a stock G it was around 35mA from memory. Many cars, from the factory, are around 25mA at idle. However, since you identified the problem the actual number you reported is irrelevent...

Also from memory, these cars tend to have internal radio issues that result in excessive current draw. I've never seen one first hand but it seems there was a document at some point discussing it.

Hi Kevin,
Im now wondering if the reading was 54mA not 5.4mA.
Im going to take apart center console this weekend and check the draw when I disconect the stereo. If its the stereo should I look for a replacement?

this is driving me nuts.

I am glad you are posting this! Thank you and if you could, please post plenty of pics for us all. I seem to be having this problem as well. Except my solution was a bit more expensive. I purchased a $300 drycell battery.

SOLVED!!!!
the cause is due to the stock stereo. This seems to be a very typical problem with 03-04' coupes. I dont know what is causing the issue inside the stereo. I found a place that can repair it but they wont give me a straight answer on the cost to repair it. It could be up to $350. I have decided to just buy a bose unit thats used from ebay.
I cant wait to not have to remove the radio fuse every time I get out of the car.

You could have just installed a simple relay. 5$, 5 minutes, and it's fixed. Why do you think another OEM radio wouldn't do exactly the same thing? It's also a PITA to replace. If you're going to the effort, might as well do a double din conversion and put in an aftermarket system.

If you can explain how to install a relay to fix this issue, please do. I havent found anyone talking about this as a fix. Definatly dont have the cash to go the double din route.

I am having the same issue, I would love for someone to explain the relay fix to me, disconnecting the battery is a pain in the ***.

I dont think there is a simple relay fix for this. I know that there was a recall for sedans having an issue with the stereo control board but im afraid the control board is not the issues with coupes. The issue is an internal stereo problem. Some people seem to think that the problem is from the stereo the switching the bose amp on even when the car is off. Well at least in my case with was not the issue. I disconnected the amp all together and still could not start my car the next day. The final test was just doing a parasitic draw test and while doing it I disconnected the stereo and the voltage draw dropped considerably.

If there is a relay trick that can fix this issue please post it hear or at least post a link to a site that explains it.

See the attached pic for a standard automotive relay wiring. You basically need to cut the power wire going to the radio (leading away from the fuse you found), and have the battery side of the wire go into pin 30, have the other side of the cut connection going to the radio tied into pin 87. Have an accessory power line (like from the fuse going to the cigarette lighter adapter) go to pin 86 and have 85 go to ground. Power to the radio will only be triggered when accessories are given power...

Here is one from amazon (doesn't have the protection diode that I like to use, but if you're not switching large current, unlikely to generate a large reverse voltage spike):


You won't even have to cut any wires if you're creative with a single small spade connector and a "add-a-fuse": http://ecx.images-amazon.com/images/...500_AA300_.jpg

Radio shack has "quick disconnects" that will fit right onto the relay ends and probably also carries spade connectors that you can fit right into the "add-a-fuse" slot - actually they also carry the same kind of relay but I'm not sure if they carry an "add-a-fuse". Most local auto stores carry that though - miniATM fuse type. No cutting, no soldering, literally 5 mins work, once you have the parts. The hard part is finding the right fuse and you've already done that. Good luck!

Nice write up "rcdash". Does this work for sure, have you tried it? The only thing that I can see wrong with it is that if your cutting the power off at the radio all together then you will have to adjust the sound settings and radio presets each time you drive the car. I defiantly think that is better then having to pull the fuse each time you get out of the car. I know that if you have to pull the fuse each time you get out of the car you have to reset those settings anyway.

I would have to ask someone else having this issue to try this method. I really dont want to pull and swap out the radio again to test it. At least not now in the dead of winter. "inneedof" Maybe you can give this a try and let us know.