Everytime it rains....

[eye30Chris]

The car wigs out. There are no codes other then my P0600 that always seems to come up and I have no idea where to start with that. I get everything from the brake and battery light staying on, the ABS light staying on, the speedo not working then suddenly working, the O/D light flashing...not always all together but usually happens when the car is started and it is raining out. A couple of weeks ago during the last rain the car actually quit on my wife, she stated warning lights started coming on, then the lights dimmed, then the wipers stopped, so she pulled over and the car died. I jumped her with a jump box and the car started no problem, I tested the alt and got 14v+ from it. The battery was reading 12.5v also.. I replaced the battery with an extra I had and the car ran flawlessly until it started raining yesterday. It hasn't stalled on me yet but I am concerned.

I have checked for a parasitic draw and came up normal. Maybe I need to check it during the rain?

246k 96 I30

[skyline084]

Nothing to do with your battery than. If it were me i would run through my whole harness wherever it's giving me problems and check for a wire being grounded, or where wires melted together or something.
If you wanna go the quick route, buy a new wire harness and call it a day

[eye30Chris]

the whole harness...I maybe over thinking this but that seems like a crazy amount of work. I have no idea what is causing the issues other then the rain being a common denominator. Installing a new harness would probably cost more to get then what I paid for the car. I appreciate the help though.

[loystock]

Check the lower engine covers (black plastic) and splash shields. Rain water could be getting into the engine compartment and spraying into the alternator and related harness, causing alternator charging voltage to go down/fluctuate. BTW, the symptoms you are seeing is a classic case of a failing alternator, in your case only when it rains. also the alt voltage is lower than spec (14.1-14.7 VDC). Check charging voltage is not fluctuating..

[eye30Chris]

The plastic shields were a little loose but in place overall. I tightened them up. I double checked the battery and alt and came up with 12.73v on battery and a steady 14.2 on the alt.(also tested 14.2v with defrost and headlights on) One thing I noticed was the alt would tap out about 14.35v when I revved the engine.(should I see more of a rise) I also checked for drop out on the B+ and came up with .031v. I wanted to also check the alt ground but I am at a loss for where to locate the alt ground. The Battery ground looks very clean and almost new. The battery is 4 months old.

[skyline084]

So you're car is worth under 400 bucks? and I can pull the harness out of my car in under twenty minutes.. both upper/lower. If it were my car, I would simply pull the harness out and check all the wires/connectors. If you don't feel like putting that much effort into it, than bring your voltmeter with you so next time it start's to act up in the rain, check your voltage and that will tell you if your alternators kicking it.

[eye30Chris]

So you're car is worth under 400 bucks?

I paid $600.00 for it. It just looked like a lot of connectors to take off for a 20 minute job. Maybe I am just letting the FSM diagrams scare me. Can I ask what year your I30/Max is?

[loystock]

The plastic shields were a little loose but in place overall. I tightened them up. I double checked the battery and alt and came up with 12.73v on battery and a steady 14.2 on the alt.(also tested 14.2v with defrost and headlights on) One thing I noticed was the alt would tap out about 14.35v when I revved the engine.(should I see more of a rise) I also checked for drop out on the B+ and came up with .031v. I wanted to also check the alt ground but I am at a loss for where to locate the alt ground. The Battery ground looks very clean and almost new. The battery is 4 months old.

Under the conditions stated above, your battery and alternator are good. The internal Voltage Regulator in the alternator should control/limit alternator charging voltage at various engine speed. The alternator ground is the engine frame where it is mounted.

Your main problem is water ingress. Try simulating it by spraying water with a garden hose. Aside from lower engine cover, how's the condition of the rubber lining close to the front of the hood?

[skyline084]

I'm just trying to point you in a direction man. I have an rb25.. not an I30. But I've worked on modern cars where there's connectors going to everything possible. It's not hard, you just have to actually do it. But from your responses, I can see you are against pulling your harness out. As loystock said, your battery is powered, and your alternator's functioning.. so that's not the problem. Whatever accessories start to short out on you when you're in the rain, is where the problem is occurring. Go pull out that section of wires, and you will most likely find what is wrong, if you can find it...

[eye30Chris]

Well I hit everything with electrical cleaner, checked the grounds and haven't had a problem again. Now I need to get this p0500 and p0600 codes knocked out. I am tired of the speedo working randomly and the ABS light coming on.

[eye30Chris]

Just as a little update

Lights just came back on and did not go away. Alternator is dead. I have the new one ready to put in after lunch.

BTW, the symptoms you are seeing is a classic case of a failing alternator, in your case only when it rains.

[eye30Chris]

The new alternator is in with little issue. Not a job I want to do again though.

[loystock]

Wow! Took that long for the alternator to finally die. I'm glad you fixed it.