Hey all,
Starting with an intro post hopefully to get some more attention to this ongoing problem I'm having. My girlfriend's car has been a real treat after years of neglect. Her 07 G35 coupe has nothing aside from coilovers and wheels. She drives it A to B. But then the fire nation attacked! First the radiator burst. Whether it was overheating before and she didn't notice I don't know. But I read it's a common issue. After replacing, doing the proper bleeding, it overheated during test drives so we replaced the water pump. Solved overheating issues. But then it threw a code for camshaft position sensors for some reason so I did those. Took it for a spin and everything seemed great. But doing a once over I saw her rear tires were done for. While she saved up funds it sat for a month. When we went to take it to have the tires put on the battery was dead so we replaced it. Got one more drive out of it and theeeeeen, nothing. Dash lights on but no start, not even a click. I proceeded to use this forum, kudos to all the wonderful answers that have gotten me this far. We had code U1000 plus Fuses 12 and 83 keep blowing. I went through all the grounds, cleaned them up and that seems to have stopped 83 from blowing and let me finally start the car again. But the moment key goes into ON I can physically hear Fuse 12 by my feet pop. Which now prevents me from coming out of drive without a trusty screwdriver in the shifter release switch. Found one post online from a Nissan tech that said the side markers are known for having a short issue tied to that fuse. So I pop out the drivers side market to look and it just came ALL the way out. As you can see it's severed. It appears maybe a previous owner did a terrible splice job into the pink wire with silver dots and the black wire with silver dots to the side marker. Maybe it was an always on mod? I'm not sure maybe someone here would know? Sorry but until her car started acting up I'd never touched one of them before so I'm learning about it as I go and think I've done a good job. Either way those two wires must've been getting real hot and melted up about a foot into the wiring harness. I trimmed those down and covered the ends hoping just to test the fuse, but to no avail. I may need to go deeper into the harness all the way back to the IPDM. Just wanna see if before I chase these wires looking for contact points around the whole car if anyone has some suggestions? Only other thing I can think to add are a few things I've checked along with other symptoms I can only assume are attributed to not having that fuse working. Thank you in advance to anyone who comes to my aid and makes me look like a saint to my gf.
Things that don't work :
1. Third brake light inside car
2. A/C controls are off (but radio is fine)
3. A/C and clock display is off
4. Side marker doesn't work (obviously)
Extra things checked :
1. Brake pedal switch is fine
2. All other exterior lights are operational
3. I THINK the ecu and BCM are okay but I couldn't tell you for sure without the dealership testing them
4. IPDM works I think ( I would love to tear that sucker open and know for sure but can it be put back together if I do? )
5. All the relay fuses work

 

I would pull an entirely new wire and abandon the melted one, no telling where else it's melted.

IPDM fuse 83 is the TCM, and back up lamp relay for the 5AT, or back up lamp switch on the 6MT. Since you're already having other lighting issues I would suspect the reverse lights are also a problem. The coupe doesn't have the "wires in the trunk harness breaking" issue so that's probably not the issue. I would tear into the ENTIRE trunk out, carpet, plastic divider trays, spare tire, everything down to the metal. There's some computer components like the HICAS and other stuff mounted to the chassis so don't be too rough pulling it all out. Then you can inspect for any janky modified wiring.

My gut suspicion is someone installed a backup camera and tapped the reverse light for signal.

 

Fuse Block - J/B (cabin fuse box) fuse 12 is a bit more problematic since it covers a LOT more stuff, NATS, rear window defroster, heated seats, AC compressor, INTERIOR CABIN LIGHTS, compass, 5AT shift lock, and some steering control stuff for the ECM.

The single common item is LIGHTS though.

Are all the interior lights stock or have them been replaced with LED lights? Same with the exterior stuff.

 

It's also possible that those fuses popping were simply because that parking light melted and took out other wires next to it. That should definitely be the first order of business, trace that wire back from one end to the other and replace the entire thing, wires don't just melt at the ends, they melt along the ENTIRE WIRE.

You can pull fuse 71 in the IPDM which sends power to the relay for the lighting system. It will disable JUST the parking light system, then see if other things work.

 

This isn't really going to help you solve the issue, but I wonder if the previous owner had done the "parking lamp to turn signal" mod? Does the wiring on the other side look hacked up?

 

@MikeG35Coupe Both sides were hacked. I think I mentioned I suspected that. There was what I think was silicone brushed on instead of using heat shrink and I didn't find any soldering so he probably wrapped them together and coated and called it good at best.

 

@cleric670 Thank you for all the info! I took the week off from busting my knuckles and putting myself upside down under the dash to investigate. Tomorrow I'll go through the process of pulling the trunk out to check on those. Rewiring the melted ones is going to be a very involved process but I will do it regardless.

 

Yes, I saw that you mentioned "maybe it was an always on mod" but that is the normal operation of those markers (always on when lights are on). Confirmation of both sides being hacked up would pretty much lead to it being a "mod", but it would have been to make them turn signals.