Electricals are going to hell
 

So it started with the 'trunk is open' light never going on. Now it thinks the trunk is open all the time. As of very recently, if the car is off (no keys in) and I turn the headlights to on, everything else (radio and fan) turn on too. If the car is running but the lights are off, the background light for the guages is always on, but dim, and the headlights seem generally dimmer too. Where do I even start looking for this? I'm guessing that some salty snow got in somewhere and is wreaking havok.

Sounds like a short, check relays fuses. Maybe take the fuse box off the mounts pull off the bottom of it and look for corrosion.

You start with inspecting. Use a bright flashlight and be prepared to be upside-down with your head in the driver's footwell for a while.



Beware of rat nests

What about a bad ground?

What pas said. If there's a bad ground somewhere in your interior wiring loom, power will redirect and ground out via the radio or trunk lights etc.

So the issue with the gauge cluster being lit up all the time fixed itself, as did the electrics turning on with the head lights. So that's good, probably. But the trunk light is still permanently on, and now it goes off when I hit the brakes, and the fuse for my brake lights blows on a daily basis, which is very annoying, unsafe, and starting to get costly.



I've looked in the foot well and everything looks ok, but I'm going to be spending several hours in a garage tonight (maybe underground at work until they ask where my parking permit is...). Does anyone know where I could find a wiring diagram?

hyundaitechinfo.com - use Internet Explorer and register for a free account

ETM Electronic Troubleshooting Manual

ACCENT(LC) >2005 > G 1.5 SOHC > Power Distribution > Schematic Diagrams



maybe?

Sounds like the brake lights have got a bad earth, or you're triggering something extra from your brake lights. Perhaps inspect the brake light harness, and the trunk light harness too.



I blew my ECU when my trunk light kept earthing on the metal frame behind the carpet.

I'd tried getting into hyundaitechinfo before and it didn't work, I didn't realize that IE was the key. I'll look there.



I took a look at it last night and couldn't find anything obviously wrong. I removed the trunk latch from the lid, there's a single wire running to it, which I presume grounds out to the the chassis when you close the lid, but connecting that wire to a ground point didn't turn the dash light off.



The wiring from the trunk lid to the chassis (for rear wiper, defroster, spoiler brake light, and latch) goes through a rubber tube on the left side of the lid that seals pretty tight on both sides, but some salty water may have gotten through that seal and cocked the whole thing up; it's right in the drainage trench that surrounds the trunk when it's open.



I replaced the brake light fuse again (3rd time) and now the trunk-open light on the dash does NOT go out when I hit the brakes. I wish it would just be consistent.

Hmmm. Okay dude, if you have a multimeter or at least a test light, check that the trunk latch wire is getting 12v. If not, it may be earthing out somewhere up the line. The wiring harness for all that runs up and over the RR wheel arch and under the RHS running board to the fuse box.



I'd also check the wiring harnesses on the tail lights themselves. I suspect that they aren't the source of the problem, but if both the brake lights and the trunk open light are involved, there's going to be a bad earth or wiring break on one of them.