Parasitic voltage loss. Pros view my readings.

[95.0mark]

Okay so I belive my car stereo head unit is causing a voltage loss. I didn't use my car for about 3 weeks and it was totally dead. I'm talking like the battery was not even in the car dead. So I bring it in to Walmart and they test/charge it. It was at 4.1v but came back to 12.6 and put over 550cca out rated 600.

Anyway, I brought it home and car obviously fired right up everything's back to normal. But obv I know something drained it so I tested voltage and it was 12.6 and its 14.45 running. All good.
Let it sit overnight and it was 12.3 in the am. Drove it to store and back and it was at like 12.9 and leveled off at 12.79 than 3 hrs later it's at 12.55

So I pulled the ground and measured current. The fucker sparks a lil when you test with mm and starts at like 550ma and levels off at 281ma exactly.

So for the hell of it I test the prizm. 5.7ma lol.

It has to be the car stereo. It's not the amp though as I disconnected the fuse under the hood and still get the 281ma draw. Just for referance it goes to 1.39 amps when door is open.

Sometimes when I push a certain button on the head unit it causes the hu lights to go out for a split second. Then other times it doesn't.

I'm thinking ground or loose connection. I had the hu out this fall.

Don't suppose there is anyway to test without removing hu is there????

Thanks

[tim]

Pull the radio fuse, see if the draw drops. If that doesnt do it then keep trying other fuses til you find which circuit is causing the draw.

[95.0mark]

Will that radio fuse still have control over the aftermarket hu? I did use factory wiring harness adapter but it has all diff speaker wire and amp power. Still should right?

[95.0mark]

Yup it's the radio. Just pulled the fuse for radio and current drops to 11.3ma

Damn taking the hu out is a pita. Guess I'm gonna have to do it though and check ground and rest of the connections. Thinkin it's ground though.

[tim]

If you are using the factory wiring you may just have a bad head unit. Not much you can do if it is wired correctly, and if it just started acting up I doubt its the wiring. Do you normally let it sit like that?

You must have bought a piece of shit deck from Harbor Freight.

[TRDon]

Hyundai doesnt make anything a pain in the ass to remove. Everythi g in it is touched by the hand of god. Ya,im mad.

[av6ateu]

Are you sure your aftermarket radio is wired correctly??? perhaps the ignition input is wired to a battery feed so it won't power down when keyed off, breh

[tim]

Are you sure your aftermarket radio is wired correctly??? perhaps the ignition input is wired to a battery feed so it won't power down when keyed off, breh

Thats why I asked if he normally lets it sit like that. If he normally ran it every few days then I guess you would never know that there was a draw.

[mnstang]

diagnose problem in a logical fashion. or just hunt and peck around long enough and you might find it.

[95.0mark]

This hu was top of the line in its day when I bought it. Alpine 9887.
I know how to wire it. Pretty simple. Ground, constant and turn on. Blk red and yellow.

I usually don't let it sit no. I've been driving the prizm now during winter usually. Might as well let the rusted out car take the brunt of winter.

[95.0mark]

So thinking it was my aftermarket stereo, I removed it and checked connections. Everything's good. I unplugged headunit and current loss is still 280 ish ma.
So upon looking at my radio fuse it is mounted in a plastic carrier along with the "room lp" fuse which runs the chime, clock, trunk lights map visor lights etc.
I was wondering why the F they were mounted together. Well upon reading the cars manual, it's a feature that allows you to quickly disconnect all parasitic draw for prolonged storage. Ok fine but 280ma is way to much draw.

I took the room lp and radio fuse out of carrier and tested each along. Radio fuse without room lp draws a whopping 12ma.

So the issue is with the room lp fuse and what it runs. What the fuck. My first issue with my beloved hyundai I guess.

Anyone know what could be going on?
I took the trunk bulb out that didn't make any change.

I'm not an electrical troubleshooting wiz. Even with my bad add new mm.

Any idea from mechanics?

I put on my hf float charger for now. I have one on my town car and it keeps it at 13.2-13.3

[taank]

I have multiple ideas. Good luck is my advice. Start unplugging things on that circuit. Start with the glove box light

[Scorpner]

Get a schematic for your car and see what's in line with the fuse.
The autozone website sometimes has them.
Or try googling: schematics hyundai (year etc.)

[tim]

If the car is going to sit for a few weeks at a time I would just use the maintainer. Big deal.

[taank]

Also how long are you letting it sit after test start? Here is how I test. If the car has a hood switch it needs to be disabled. Set up meter leaving battery connected. Start vehicle let idle. Shut off after 1 min. Remove keys, shut door. Lock doors with fob. Now with out disrupting the test leads. Unhook the negative battery terminal. I use vise grips to hold leads to battery. Keep cable separated from battery for 30 min. Check draw after 30 min. The bcm has keep alive memory and takes a long time to power down.